view cartView Cart

Select Your Vehicle


Filter Questions and Answers:


reset filter

Expert Answers about Wiring


  • Troubleshooting a Right Turn Signal on a 7-Way of a 2000 Ford F-150
  • First thing you should do at this point is test the 7-way of the wiring harness with a circuit tester part # 3808 for voltage on all of the right pins when the taillight signals are being applied. Just like in the video I attached. If the voltage checks out there but the trailer lights still don't function right then the problem is on the trailer wiring. That would mean that problem is either due to a ground issue or a short issue. Make sure that the trailer side connector are clean...
    view full answer...

  • Troubleshooting Trailer Blinker that Stays Solid
  • First thing you should do at this point is test the 4-way of the wiring harness with a circuit tester part # 3808 for voltage on all of the right pins when the taillight signals are being applied. Just like in the video I attached. If the voltage checks out there but the trailer lights still don't function right then the problem is on the trailer wiring. That would mean that problem is either due to a ground issue or a short issue. Make sure that the trailer side connector are clean...
    view full answer...

  • Turn Signal On 2012 Kia Sorrento SX Hyperflashing After Installing Wiring Trailer Harness
  • Sounds like you are experiencing what is termed 'Hyperflashing'. My best recommendation is to remove the # C56146KIT and see if the problem still persists. If it does there is a problem in the vehicle wiring. If the problem goes away, then the converter is probably bad and the harness needs to be replaced. If you do find you need to replace it I recommend the Tow Ready Wiring, part # 119147KIT. We have had good success with our customers that have used this kit. Please keep...
    view full answer...

  • Trailer Light Fuse in 2004 Chevy Silverado Blows When Any Trailer is Connected to 7-way
  • Since you have the issue with your truck's trailer left turn fuse blowing no matter what trailer is connected, the issue is likely to be in the truck's 7-way socket or the wiring leading to it. Corrosion can build up in the truck's 7-way socket - either on the pin contacts themselves or even inside the back of the connector - and this can cause two circuits, such as the trailer left turn/brake circuit and the 12V auxiliary trailer power circuit, to become bridged together. The round...
    view full answer...

  • Reading 12-Volts on 6-way Connector of Kaufman Tilt Bed Trailer
  • Do you mean that you're using a circuit tester on your 6-way connector on the trailer (not the truck) and you're reading 12 volts on one of the pins? The only way that would happen would be if you had a battery mounted on the trailer. Typically, the battery is connected to the 12-volt supply circuit off the 6-way to receive a maintenance charge.
    view full answer...

  • Troubleshooting Left Stop/Turn Light Not Functioning On Trailer
  • Sounds like you are trying to figure out why the left brake light on your trailer isn't functioning but the rest of the trailer lighting seems to be working. Typically this problem is due to a bad ground on the light assembly. The light grounds should be attached to clean and corrosion free bare metal surfaces. If there is anything between a light ground and the metal trailer frame or if the trailer has an aluminum frame, tilt bed, or folding tongue, any of these things can interrupt...
    view full answer...

  • Electric Trailer Brakes Make Noise But Will Not Engage
  • The first thing you will want to check is the output voltage on the brake controller. If it is set too low it will not send enough power back to engage the trailer brakes. For testing purposes it is easiest to set it to full power. Using a meter or circuit tester like # 40376 make sure that power is getting back to the trailer connector, which it does sound like it is. Then with the trailer connected make sure power is getting to the brake magnets which again it sounds like it is. That...
    view full answer...

  • Left Blinker Flashes Fast After Installing Trailer Wiring Harness on a 2014 Chevy Camaro
  • In order to determine the functions of the wires on your 2014 Chevy Camaro you will need to use the included circuit tester that came with # 119147KIT. What you are describing sounds like hyperflashing which can happen when using LED lights but usually not stock LED lights on a vehicle. If the issue is happening on a trailer then the hyperflashing is a result of not enough load on the system. Installing a load resistor such as # P230004A in line of the affected circuit would cause more...
    view full answer...

  • Troubleshooting Trailer that Right Turn Signal Comes On But Won't Blink
  • First you will want to check the right turn signal of the vehicle wiring connector to make determine where the problem is. It's either the tow vehicle or the trailer. You will want to use a circuit tester like part # 3808 to check the pin on your connector for intermittent voltage when the blinker is applied. If the voltage of the vehicle checks out like it should then I would suspect the problem is either that the light assembly isn't grounding properly or it is shorting out to the...
    view full answer...

  • Troubleshooting 4-Way Harness On 2013 Ford F-150 And Trailer Wiring
  • If you installed the 4-way connector at the back of your 2013 Ford F-150, you can check the connector first to make sure it is wired correctly. I recommend using a circuit tester like part # 3808 and check each pin for function. You want to make sure the pin connected to the yellow wire shows current for your left turn and brakes, green is for right turn and brakes, brown is for the tail lights, and the white wire is the ground which should be secured to a clean, bare metal surface. You...
    view full answer...

  • No 12 Volt Power to Trailer Connector on a 2002 Chevy Silverado
  • This is not an uncommon situation for your generation of Chevy Silverado. If you remove the cover on the power distribution box, look for a row of larger fuses on the left side of the box (if facing the motor from the front of the truck). If there is no fuse or a blown fuse in the slot closest to the front of the truck in that row then you will need to install a new 40 amp fuse. If there is no wire attached to the post nearest that fuse location you will have to manually run a wire from...
    view full answer...

  • Low Beam Headlight Not Working But High Beam Does Work
  • It sounds like there could be a fuse blown or damage or corrosion in the bulb socket. Bulbs that have both high and low beam functions have 2 filaments in them so it is also possible that the low beam filament has burned out. If you can tell me the year, make, and model of the vehicle I can recommend some replacement bulbs.
    view full answer...

  • Troubleshooting Brake Light/Left Turn Signal on a Trailer Towed by 1999 Chevrolet Silverado
  • The first thing I would test is the trailer connector on your 1999 Chevrolet Silverado using a circuit tester like part # 3808 to see if the problem lies in the trailer or in your vehicle. See the linked video to see how to do this. You will be testing for brake/stop light functionality of the circuit and this will tell you if the problem is on the truck or the trailer. Also to ensure that your trailer connector is wired properly, we recommend using the circuit tester to match pins by function....
    view full answer...

  • Brake Controller Does Not Work when Using 7-Pole Round to 7-Pole Blade Adapter
  • It does sound like something is mismatched in the wiring. Either the truck or the trailer would appear to not be following the standard pin out. On the output side of adapter # HM47425 the brake pin is in the 5 oclock position if looking at the pins. If looking at the back of it where the wires attach it would be in the 7 oclock position. I have included a link to a help article that shows how different trailer connectors are normally pinned out so you can compare them with what you...
    view full answer...

  • Brake Lights on 2012 Semi Trailer Work But Not Brake Lights on 2004 Freightliner
  • Since your semi trailer brake lights are working but the tractor's brake lights are not working, it sounds like the wiring for the trailer lighting is independent of the tractor's brake lights. If all of the trailer lights operate as they are supposed to then I would first check the fuse panel in the tractor for a blown brake light fuse or perhaps for corrosion in the fuse holder. You can also check the individual brake lights on the tractor for signs of a weak ground connection (especially...
    view full answer...

  • Blinkers Do Not Work with Running Lights On on a 2007 Freightliner XL Classic
  • You will first need to make sure that the new tail lights are wired the same as the old ones. There are basically 2 types of wiring systems. First there is a 2-wire system that has combined turn signals and brake lights on the same circuit/bulb. And there is a 3-wire system that has separate circuits/wires and bulbs for turn signals and brake lights. On many tail lights the functions of the wires is listed on the back of the assembly. Since there isn't a standard wire color/function code...
    view full answer...

  • Trailer Brake Lights and Turn Signals Work But Running Lights Do Not
  • In order to determine where the problem is you will first need to test the connector on your 2011 Chevy Silverado without the trailer plugged in. Basically you will use a circuit tester such as # 3808. Turn the running lights to the on position in the truck. Then test the connector to see if the running light circuit has power. If it does not then the issue is on the vehicle side. It could be a blown tow package fuse. Using the owners manual, find the location of the tow package fuses...
    view full answer...

  • Rental Trailer Lights Not Working with 2011 Mercedes ML350 and Prodigy RF Brake Controller
  • The Prodigy RF brake controller # 90250 is a sensitive unit. You will need to make sure you follow the hooking up procedures to the letter or it may not work properly. If you still have problems make sure that none of the tow package fuses on your 2011 Mercedes ML350 are blown. It is also possible that the trailer lights were the problem. I would assume the rental place would check that and not leave it up to you! If the trailer happened to have LED lights you would need a special...
    view full answer...

  • Troubleshooting Trailer Brakes that Lock Up After Rewiring Trailer
  • It sounds like the 12 volt circuit of the 7-way wiring is shorting out to the brake output circuit which is causing the brakes to lock up when the trailer is connected to the tow vehicle. This is most likely due to exposed wiring from when you rewired the trailer. I would go over all the connections you made looking for exposed wire and fix as necessary. I attached an FAQ article on trailer wiring for you to check out as well.
    view full answer...

  • Troubleshooting Trailer Taillight Converter Installed on 2006 Volkswagen GTI
  • When the turn signals are activated, and you get 'bleed over' into the other turn signal, it can indicate a poor ground connection. Check the ground connection on the trailer, where the white ground wire from the trailer connector connects to the trailer. This is usually found on the trailer tongue. Make sure the connection is secure, and not corroded. Check the grounding point for each lamp. Some lamps have a separate ground wire that connects to the trailer frame, others ground by the...
    view full answer...

  • Troubleshooting Dim Lights on Trailer and Some that Don't Turn On
  • It sounds like there is either a lot of corrosion on either the vehicle's trailer connector or the connector on the trailer. Or, your trailer has a ground problem. First thing you should try is thoroughly cleaning the pins of the connectors with fine grit sandpaper to get the pins down to bare metal. The main connector grounds should be attached to clean and corrosion free bare metal surfaces. The light grounds should also be attached to clean and corrosion free bare metal surfaces....
    view full answer...

  • Running Lights on Trailer Stay On All the Time
  • This sounds like a ground issue or it could also be a short. Look for any pinched or frayed wires on the trailer and fix as needed. This could cause a short resulting in constant power draw. Ground problems normally show up when there is more draw on a system such as when you have the running lights on and then use another function like a turn signal or brake light. Make sure that the vehicle side and trailer side connectors are clean and free of corrosion inside and out. The main connector...
    view full answer...

  • How Many Circuits are Supported by the Optronics 7 Pole to 5 Pole Flat Wired Adapter # A57WB
  • Thank you for your recent purchases from etrailer. The Optronics 7 Pole to 5 Pole Flat Wired Adapter # A57WB that you purchased is intended to allow a tow vehicle with an RV-style 7-way blade type trailer socket to connect to a trailer that uses a 5-pole flat type connector. The linked article on trailer wiring shows these and other connector types commonly in use. The 5th wire on a typical 5-pole trailer is usually blue in color and is there to carry signals for electric trailer...
    view full answer...

  • Troubleshooting Trailer Left Turn/Brake Light Not Functioning on Trailer Wiring
  • Most likely the problem is the ground of the trailer's left side turn signal and brake light. Make sure that the vehicle side and trailer side connectors are clean and free of corrosion inside and out. The main connector grounds should be attached to clean and corrosion free bare metal surfaces. The light grounds should also be attached to clean and corrosion free bare metal surfaces. To rule out your tow vehicle as the problem you can use a circuit tester like part # 3808 to test...
    view full answer...

  • Troubleshooting 7-way On 2004 Ford F150 Not Showing Left Turn Signal
  • If you've tested the 7-way on the vehicle, and have determined that you have no signal on the left turn signal pin, closely examine the trailer connector. Make sure it's not damaged or excessively corroded and clean/replace if necessary. If the trailer connector checks out okay, take a look at the wiring harness that feeds the 7-way, right behind the connector. Find the yellow wire in the harness and use a circuit tester like part # 40376 to test the wire as a helper activates the left...
    view full answer...

  • Troubleshooting Trailer Brake Lights that Don't Function With Headlights or Running Lights On
  • This sounds like a ground issue. Ground problems normally show up when there is more draw on a system such as when you have the running lights on and then use another function like a turn signal or brake light. Make sure that the vehicle side and trailer side connectors are clean and free of corrosion inside and out. The main connector grounds should be attached to clean and corrosion free bare metal surfaces. The light grounds should also be attached to clean and corrosion free bare...
    view full answer...

  • Troubleshooting Dim, Pulsating Trailer Running Lights
  • It sounds like the problem is on the trailer wiring. Make sure that the vehicle side and trailer side connectors are clean and free of corrosion inside and out. The main connector grounds should be attached to clean and corrosion free bare metal surfaces. The light grounds should also be attached to clean and corrosion free bare metal surfaces. If there is anything between a light ground and the metal trailer frame or if the trailer has an aluminum frame, tilt bed, or folding tongue,...
    view full answer...

  • Troubleshooting Trailer Lighting Where Only One Running Light Works
  • Since all of your trailer lights operate properly with the exception of one of the running lights, this tells us that the vehicle wiring harness is probably working properly. I would first carefully check the bad light's ground and power wires to ensure that both are secured. If the light uses a separate ground wire, usually a white wire like on # MCL36AB, that ground wire needs to be affixed to the trailer frame, to a clean rust-free bare metal surface. If the light is the type that...
    view full answer...

  • Troubleshooting Honda Ridgeline Blinkers that Stop Working when Brakes are Applied
  • Typically when this issue arises on a Honda Ridgeline the issue is that the "small lights" fuse under the hood is blown. This may or may not have been related to the trailer wiring you installed.
    view full answer...

  • Troubleshooting a Trailer that Taillights, Blinkers Both Flash and Only One Running Light
  • It sounds like the problem is the wiring of your truck like it sounds you have determined already. What I would do is use a circuit tester like part # 3808 to test the circuits of your 7-way while a buddy applies the different taillight functions. Use the diagram I attached to the right for more info. The problem could be as simple as corrosion on the connector that needs to be cleaned off (inside or outside of the connector), or it could be that the wires of the connector have shorted...
    view full answer...

  • Troubleshooting Inactive 7-way 12 Volt Accessory Circuit of 2007 GMC Sierra 1500
  • I am going to go out on limb and say that you are trying to activate the 12 volt accessory circuit on the 7-way of your 2007 GMC Sierra 1500 and it isn't working so you are looking for a fuse to replace? Actually what is happening on your truck is that there are a few underhood connections that need to be made in order for this circuit to be completely activated. For more info on this check out the FAQ article I attached to the right and scroll down to the section titled, "Finalizing...
    view full answer...

  • Troubleshooting Right Stop/Turn Circuit on Aluminum Trailer
  • It sounds like you have narrowed the problem down to being somewhere on the right stop/turn circuit (green wire) on the trailer. If you can use your circuit tester to test that circuit as close to the light assembly as possible to see if the light is getting voltage or not. The other possible problem is that the ground of the assembly isn't sufficient. Make sure that the vehicle side and trailer side connectors are clean and free of corrosion inside and out. The main connector grounds...
    view full answer...

  • Troubleshooting Trailer Brakes that Lock Up When Connected to Trailer Wiring
  • This is a fairly common problem for trailer setups that use 6-way connectors like the # PK11604 that you referenced. The issue is that there is two accepted ways the connector can be wired up. The only difference between the two setup is that the brake output circuit and the 12 volt accessory circuits are swapped. It sounds like your vehicle is wired one way and the trailer is wired the other way. What you will need to do is swap the two circuits on either the trailer or the truck....
    view full answer...

  • Horse Trailer Brakes Lock Up When Connected to 1999 Ford F-250
  • It sounds like either the trailer side connector is not pinned to match the vehicle side connector or there is a short circuit (possibly due to corrosion on the pin or inside the trailer connectors) causing the brakes on the trailer to lock up. The easiest thing to check first is for dirt/corrosion on the pins and inside each of the trailer connectors. Then you can make sure that the trailer side connector is wired up to work properly with the vehicle side connector. I have included...
    view full answer...

  • Troubleshooting Non-Functioning Running Lights on Trailer Towed By 2014 Nissan Frontier
  • It sounds as if you might have a blown fuse. You'll need to check the diagram on the lid of the fuse box under the hood, and look for a fuse for the trailer running or parking light circuit, and replace it. Before plugging the trailer into the vehicle, you'll want to closely examine the running light circuit for any shorts that would have caused the fuses to blow. Start at the trailer connector, and examine it for damage. Trace the running light circuit (usually a brown wire) back to...
    view full answer...

  • Troubleshooting Trailer Left Turn Signal That's Not Working
  • Without knowing the year, make and model of the vehicle, I can't really provide any specifics but I can provide you some general things to check. The first thing you'll want to do is determine if the problem is in the vehicle or the trailer wiring. The easiest way to do this is to plug in another trailer if one's available and see if the problem persists. If this isn't possible, use a circuit tester like part # 40376 on the trailer connector on the tow vehicle. Activate the left turn...
    view full answer...

  • Does a Breakaway System Battery Affect Everyday Trailer Brake Performance
  • Electric trailer brakes can work on a trailer that doesn't have a breakaway system. So the answer to your question is no, the breakaway battery would not affect how normal trailer brakes will operate under normal circumstances. The only time the breakaway battery will change how the brakes are performing is when the pin of the system has been pulled and the voltage of the battery is being applied to the brake assemblies. I attached an FAQ on breakaway systems plus an FAQ on troubleshooting...
    view full answer...

  • Troubleshooting Install of Tow Ready Wiring Kit # 119179 Doesn't Work With Running Lights are On
  • The Trailer Wiring Kit part # 119179 fits several vehicles and several different configurations of vehicle wiring. Without knowing what vehicle you have or what style of taillights you have on your vehicle it would be hard for me to say for certain. Based on the description of how you installed the harness it sounds like you have it wired up like a 2 wire system. It could be possible that you have a 3 wire system and would need to wire it up like the illustration I attached.
    view full answer...

  • Troubleshooting Factory Trailer Wiring for 2003 Ford F250
  • First I recommend cleaning the connector and make sure there is no corrosion on the pins. Check the wires at the back of the plug. You may need to remove the wires from the connector as corrosion can build up in the connector. If all of the connection points are corrosion free, then begin testing the wires themselves. Since you are not receiving a signal on some of the pins I recommend tracing those wires back till you find a point where the signal is active. It may be that connection...
    view full answer...

  • Troubleshooting 4-Way Wire Harness installation On 2009 Cadillac SRX
  • The wiring harnesses and kit, part # HM48895 and part # HM46155 you referenced in your question are not designed to be a fit for your 2009 Cadillac SRX. If you find that you have the correct wire harness for your SRX you can check the wiring to make sure all of the wires have been connected as the instructions state. Also, you will want to make sure the ground wire has been secured to a clean bare metal surface. Loose or corroded grounds can cause some of the same problems you described....
    view full answer...

  • 2008 Chevrolet 2500HD 12 Volt Battery Wire for 7-Way Connector
  • Sounds like you have the correct 7 way connector and the correct pins, but you are missing the wire that runs from the power posts to the connector. First let's make sure. In the under hood accessory fuse block there are two power posts on the engine side of the block. The post closest to the front of the truck should have a wire connected to it that runs back to the factory trailer connector and provides 12 volt power at the 1:00 position as you have stated. If the wire is not already...
    view full answer...

  • How to Test the Trailer Light Functions of a Trailer with a 4-Way
  • There is, but I will warn you it's pretty expensive. The Hopkins Tow Doctor Trailer End Test Unit # HM50928 is designed to test the connector on a trailer for function and would be perfect for what you are trying to do. Check out the review video I attached. A much more inexpensive option would be to use a jumper wire from a car battery's positive post to put voltage on all of the pins of your trailer's connector. You would need to test the three male pins next to the female pin....
    view full answer...

  • Troubleshooting Trailer Wiring That all Blinks When Right Turn Signal is Applied
  • You are having some interesting wiring issues on your trailer. First thing I would recommend you do is check to make sure all of the wires are grounded properly. Ground issues can cause bizarre trailer wiring behavior. Each lamp should be grounded either by its mounting studs being in direct connection with the trailer frame or by each lamp's ground wire being connected to the trailer frame. Next, you will need to inspect the wiring from the connector to the light assemblies looking...
    view full answer...

  • Replacing 4-Pole Trailer Connector on Trailer With 7 Different Circuits Feeding It
  • It sounds like you've got a pretty good handle on what you're dealing with. You're correct, the green is right turn/brake, yellow is left turn/brake, black/green is right taillight and black/yellow is left taillight. The remaining wires are almost certainly grounds. I'm guessing you're not the original owner of the trailer or the person who wired it last time. Rather than grounding each trailer lamp directly to the trailer frame by its mounting studs or individual ground wires connected...
    view full answer...

  • Troubleshooting Trailer Wiring that Blinkers Dont Work When Headlights are On 2007 Toyota 4Runner
  • This sounds like a ground issue. Ground problems normally show up when there is more draw on a system such as when you have the running lights on and then use another function like a turn signal or brake light. Make sure that the vehicle side and trailer side connectors are clean and free of corrosion inside and out. The main connector grounds should be attached to clean and corrosion free bare metal surfaces. The light grounds should also be attached to clean and corrosion free bare...
    view full answer...

  • Troubleshooting 7-Way Connector of 2006 Toyota Sequoia With No 12-Volt Feed at 7-Way
  • If your 7-way on your Sequoia was installed at the factory, the 12-volt circuit should be active. Check the fuse box under the hood for a blown or missing fuse. If there's no blown fuse, you trace the 12-volt circuit from the rear of the vehicle looking for a loose connection, but abandoning the original and installing your own circuit as described below might be the simplest course of action. If the 7-way was installed aftermarket, check the terminal for the 12-volt pin at the rear...
    view full answer...

  • Turn Signal Not Working when Using Brakes and Using Hopkins 40955 Wiring Kit
  • Since you have a new trailer connector on your vehicle that tells us that the issue is likely on the trailer somewhere and it sounds to me like it is a bad ground. Make sure all your ground connections are good and clean. There will be a ground connection coming from the trailer connector to somewhere on the trailer tongue and each of your trailer lights should have a ground connection through either a ground wire ran to the trailer frame or grounded through a mounting stud on the light...
    view full answer...

  • Troubleshooting a Trailer Right Brake Light Won't Function
  • It sounds like the problem is on the trailer and is ground related. I would inspect the grounds of the light assembly you have installed on the right side of your trailer and make sure it is connected to a clean metal surface. A lot of assemblies ground through their mounting hardware so you will want to make sure that the assemblies are connected to a clean metal surface. The brake lights will require a better ground than the blinker since it only illuminates one circuit for the blinker. I...
    view full answer...

  • Trailer Connector on 1994 Ford F-250 Only has 12 Volt Power on the Center Pin
  • If it is really a 6-Way and not a 7-Way blade style trailer connector then the center pin being hot would indicate that particular pin is the 12 volt power circuit. But the other functions not working could mean that tow package wiring fuses and/or relays are missing or need to be replaced. Check the truck owners manual to find the locations of any and all fuses related to the tow package wiring. If the wiring was added and is not factory then you will need to check the wiring connections...
    view full answer...

  • Trailer Brake and Tail Lights Go Out when Headlights on 2000 Chevy Silverado Come On
  • This sounds like a ground issue. Ground problems normally show up when there is more draw on a system such as when you have the running lights on and then use another function like a turn signal or brake light. Make sure that the vehicle side and trailer side connectors are clean and free of corrosion inside and out. The main connector grounds should be attached to clean and corrosion free bare metal surfaces. The light grounds should also be attached to clean and corrosion free bare...
    view full answer...

  • Trailer Lights are Erratic After Switching to LED Lights
  • Jesus is a good driver, but not a trailer expert. And that's ok because your trailer is not possessed . . . well, it could be, but that is not what is causing this problem. What you have here is a ground problem. Ground problems can cause all sorts of funky things to happen. The good news is ground problems are usually very easy to fix. The bad news is that you have to find the problem before you can fix it. Ground problems normally show up when there is more draw on a system such as...
    view full answer...

  • LED Trailer Lamps Stay Illuminated When Tow Vehicle is Shut Off
  • When the tow vehicle is shut off, the only pin on its 7-way trailer connector that should show any power is the 12-volt accessory circuit, which is the pin in the 1:00 position. If the trailer lights are illuminating when the tow vehicle is shut off, the only possibility is that there's a small short either in the 7-way connector or in your adapter that is allowing some power from the 12-volt accessory circuit to bleed over into one of the lighting circuits. With the vehicle shut off,...
    view full answer...

  • Trailer Lights Go Out When 2002 GMC Yukon Headlights are Turned On
  • This sounds like 1 of 2 things. Either a bad ground or the vehicle side wiring is being overloaded (which can happen if there are a lot of lights on the trailer). Ground problems normally show up when there is more draw on a system such as when you have the running lights on and then use another function like a turn signal or brake light. Make sure that the vehicle side and trailer side connectors are clean and free of corrosion inside and out. The main connector grounds should be...
    view full answer...

  • Troubleshooting 7-Way on a 2001 Chevy Truck that All Circuits aren't Functioning
  • The first place you will want to check is the fuse box on your 2001 Chevy 2500 Silverado. You will want to look for the trailer wiring fuses and replace them as needed. Since I am not entirely sure what circuits on your truck aren't working it could be you are missing a couple connections under the hood of your truck for the brake controller wiring to be completed. Check out the FAQ article I attached to the right for more info on this. Corrosion in the 7-way connector or on the back...
    view full answer...

  • No Power On 12 Volt Circuit on 7-Way Trailer Connector on a 2006 GMC Sierra 2500HD
  • On some GM trucks, even those with factory tow package, the wiring is not always complete. You may need to manually run a wire from the front of the truck to the back of the 7-Way. I have included a link to the right that should help. It talks about the under the hood connections that might need to be made when installing a brake controller but also mentions the 12 volt power wire. Presumably, if the wire is attached directly the positive terminal, it would have power all the time. But...
    view full answer...

  • Trailer Connected to 2012 Ram 2500 Causes Truck Reverse Lights to Come On
  • The center pin on your 2012 Ram 2500 is probably wired to the reverse lights. The center pin on the trailer is probably wired to a trailer mounted battery or breakaway system battery and it is back feeding to the trucks reverse lights. The trailer could have more than 1 battery on it. What you will need to do is figure out what is wired to that center pin on the trailer side. I have included a picture that shows the pin out functions of a vehicle side and trailer side 7-Way that...
    view full answer...

  • Troubleshooting Running Lights and Dash on 1986 Ford Econoline Jayco Motorhome
  • You said you checked the fuses. Some motorhomes have fuse boxes in multiple locations, inside the engine compartment, inside the cab under the dash, and even in the camper sewer/electrical compartment. Sometimes a fuse may appear to be in good condition, but really needs replacing. To rule that out, take a new fuse that has the same rating and insert it into the proper location. If the problem is a short, and the next fuse that you insert shorts out as well, you will need to use the...
    view full answer...

  • Troubleshooting Dash Lights and Running Lights not Working in 1986 Jayco Econoline Class C
  • Without knowing more about the problem you are experiencing, like whether it's the vehicle that's experiencing the problems or the trailer wiring, the best recommendation I could give would be to check the fuse box looking for running light and dash light circuits and replace the fuses as needed as this would be the most likely cause of the problem you have. Beyond that you would want to track down wiring diagrams of your vehicle to see if wiring is damaged and needs replacing. At this...
    view full answer...

  • Troubleshooting Trailer Running Light Circuit that Quit Working on a Tow Vehicle
  • Sounds like a blown fuse on your tow vehicle. Check out the fuse panel and look for tow package related fuses and check them all. Most likely one will be blown and need to be replaced. I attached an FAQ on 4-way troubleshooting for you to check out as well.
    view full answer...

  • Troubleshooting Trailer Blinkers that Both Blink When Either Turn Signal is Applied
  • It sounds like you have the blinker circuit of your 1998 F150 run to the running lights circuit on your trailer wiring so when the blinker is applied both of your running lights are flashing. Any time you see trailer lighting that illuminates dimly when the wrong circuit is applied is usually indicates that there is a weak ground on the trailer wiring circuit. How that all works is beyond me, but what you will want to do is return the trailer to the previous wiring configuration you...
    view full answer...

  • Troubleshooting Trailer Lights that Don't Function Properly Vehicle Head or Running Lights are On
  • This sounds like a ground issue. Ground problems normally show up when there is more draw on a system such as when you have the running lights on and then use another function like a turn signal or brake light. Make sure that the vehicle side and trailer side connectors are clean and free of corrosion inside and out. The main connector grounds should be attached to clean and corrosion free bare metal surfaces. The light grounds should also be attached to clean and corrosion free bare metal...
    view full answer...

  • Troubleshooting Why Trailer Lights Go Out When You Hit the Brakes
  • It sounds to me like you may have a ground problem. There are several places to look for a poor ground connection. I recommend starting with the trailer connector on the trailer. Check to make sure that the ground wire is secured to a clean metal surface on the trailer. In addition, each lamp/signal will also need to be grounded. Typically the lamp/signal is grounded through the mounting bolts having direct contact with the trailer frame. If the area that the lights are mounted to...
    view full answer...

  • Rental Trailer Caused Fuse to Blow Now Trailer Lights Won't Work After Replacing Fuse
  • It sounds like the rental trailer had a short and caused the fuse to blow. It could have actually caused more than one fuse to blow (or a relay if your vehicle also uses relays for the tow package wiring). Use the vehicle owner's manual to find all fuse and relay locations related to the tow package wiring to see if there is something else that needs to be replaced. To test the vehicle side trailer wiring you can follow the help article I have linked to the right.
    view full answer...

  • Troubleshooting Left Turn Trailer Taillight Not Functioning
  • Without knowing what vehicle you have or what trailer wiring harness you have installed on that vehicle it is pretty difficult for me to say what could be wrong, but since you checked the tow package fuses you have at least ruled that out as well as determined that the problem is most likely on the vehicle side. However, if you haven't already I would recommend you use a circuit tester like part # 3808 to verify that there is not voltage on the left turn/stop circuit when the left blinker...
    view full answer...

  • Troubleshooting 2005 Chevrolet Silverado 1500 7-Way Trailer Connector With No Power
  • Normally, the power wire for a 7-way connector will be coiled up and under the master cylinder if it is not attached already. It should be connected to the post located right by the STUD # 1. You will need to make sure there is a fuse in the STUD # 1 location as well. This should complete the power connection to your 7-way connector. You can use a circuit tester like part # 3808 to test the wire leading into the back of the connector on your 2005 Chevrolet Silverado 1500. If it is receiving...
    view full answer...

  • Troubleshooting Trailer Lights After Installing Hopkins Replacement 4-Way Connector # HM48192
  • The part you referenced, Hopkins Endurance Quick-Fix Replacement 4-Way Flat Trailer Connector # HM48192, has LEDs to indicate the presence of a signal. Since your connector's LEDs are lighting up this tells us that the signals from your tow vehicle 4-way connector are reaching the Hopkins connector. Since none of your trailer lights are working, the most likely explanation is a bad ground. Check the trailer's ground wire that connects to the trailer frame. This will typically be a white...
    view full answer...

  • Troubleshooting Trailer Taillights that Stop Working When Brake Pedal is Depressed
  • This sounds like a ground issue. Ground problems normally show up when there is more draw on a system such as when you have the running lights on and then use another function like a turn signal or brake light. Make sure that the vehicle side and trailer side connectors are clean and free of corrosion inside and out. The main connector grounds should be attached to clean and corrosion free bare metal surfaces. The light grounds should also be attached to clean and corrosion free bare metal...
    view full answer...

  • Troubleshooting a Brake Controller not Working When Used with a 7-way to 6-Way Adapter
  • A 6-Way trailer connector can be pinned in 2 different ways. The center pin can either be 12 volt power or trailer brakes. You will need to determine which way your trailer is wired up and then make sure the adapter you have is wired up the same way. This would explain the issues you are having with the brake controller not working. Next thing you will want to do is test the circuits of the 7-way with a circuit tester like part # 3808 to make sure all of the circuits are active. If so,...
    view full answer...

  • Troubleshooting Trailer Taillight Signals that Stop Working When the Running Lights are On
  • This sounds like a ground issue. Ground problems normally show up when there is more draw on a system such as when you have the running lights on and then use another function like a turn signal or brake light. Make sure that the vehicle side and trailer side connectors are clean and free of corrosion inside and out. The main connector grounds should be attached to clean and corrosion free bare metal surfaces. The light grounds should also be attached to clean and corrosion free bare metal...
    view full answer...

  • Trailer Wiring Harness Left Turn/Brake Light Circuit Keep Failing on a 2011 Hyundai Tucson
  • Since it sounds like this is a recurring problem it might indicate a problem on the trailer, specifically a short or overdraw situation that is causing the failure. The only reason I think this might be the case is because it is unlikely that 2 harnesses would fail in the same way. You will want to check the trailer wiring for any pinched or frayed wires that might be causing a short. Also make sure that the vehicle and trailer side connectors are clean and free of corrosion. Ultimately...
    view full answer...

  • Troubleshooting Trailer Running Lights Function on 2011 Porsche Cayenne Wiring Harness Install
  • The circuit that carries the stop/turn circuit is not the same circuit as the running light circuit. The circuit on the 4-way you have that has a brown wire leaving it is the running light circuit. You will need to test this circuit. If this circuit does not have voltage on it the problem is in the wiring of the harness most likely. You would want to review the install instruction I attached to the right to verify that it is installed correctly. If the voltage is there then the problem...
    view full answer...

  • No Power from Ford Brake Controller to 7-Way Trailer Connector on 2010 Ford F-150
  • I think this might be the ultra-rare Ford dummy harness issue. A few years ago I had a customer with a similar problem. It took days of troubleshooting and a savvy Ford tech at a dealership to determine that the harness behind the dash that the controller plugs into was not a complete harness so that could be what is going on. Ford would have to provide the harness. If you have the correct harness, which is likely given how rare this issue is, then it could be another problem with bent...
    view full answer...

  • No Power to 7-Way Trailer Connector on a 2004 Ford F-150
  • It sounds like a possible tow package fuse has blown on your 2004 Ford F-150. You will want to use the truck owners manual to find the locations of all fuses/relays associated with the tow package wiring to check them. The 12 volt pin on a 7-Way does not affect the regular trailer lights and the fact that everything stopped working with the interior lights is what makes me think the issue is related to the tow package fuses (specifically the one that controls the 12 volt circuit on the...
    view full answer...

  • No Brake Light Signal on 2000 Chevy Silverado Trailer Connector
  • If the 4 pole on the truck is factory installed, and you aren't getting any signal on the trailer connector when the brake pedal is pressed a blown fuse is the most likely culprit. Check the under-hood fuse box for a blown fuse. The lid of the fuse box should have a diagram on it that shows which fuse protects which circuit. If there is a blown fuse, it could have been caused by a short in the wiring of the trailer. Once the fuse is located and replaced, be sure to closely examine the...
    view full answer...

  • Trailer Lights Work On One Vehicle But Not Another
  • It sounds like the problem is either on the connector or on your VW. First, you will need to have someone help you test your connector. Using a circuit tester like part # 3808, you will want to test each pin on the vehicle connector for function to make sure you are receiving a signal. Check for any corrosion in the harness. Any corrosion can cause problems on a wiring circuit. Make sure the ground wire is securely fastened to a clean, bare metal surface. If everything checks...
    view full answer...

  • Troubleshooting Trailer Wiring Harness that Shorts Out Running Light Circuit when Connected
  • If when your trailer harness is installed (correctly) it causes fuses to blow and prevents your left blinker from functioning it would be safe to assume that the harness is bad and needs to be replaced. You might double check that all of the connections were made solidly and there wasn't any exposed wire shorting out at all. I attached an FAQ on troubleshooting 4-ways plus a video on how to test them although it sounds like your harness has already been determined to be shorted out. Most...
    view full answer...

  • Vehicle Side 4-Way Trailer Connector Plug-in Circuit Tester Lights Light Up when Connected
  • If the lights on a 4-Way trailer connector tester such as # I26 or # 30512 light up when connected that means that those circuits are receiving power. It doesn't take much power to light up these small LED lights so even residual current could set them off. This is typically more likely on aftermarket installed trailer wiring harnesses that have a connection to the battery to power the trailer lights. It could also indicate a short circuit if the lights stay on all the time. The likely...
    view full answer...

  • Troubleshooting Trailer Wiring that the Turn Signals Activate with Blinkers
  • The issue you are experiencing is due to the fact that your trailer has separate trailer wiring circuits, meaning the turn signals and the brake lights are on separate bulbs and the trailer wiring harness # 56146KIT you installed is designed to operate combined trailer taillights, meaning the turn signals and brake lights are on the same bulb. What you are going to need to do is install the taillight signal converter part # 118158 on the wiring of your trailer. Once installed the red...
    view full answer...

  • Solution for Land Rover LR4 that won't Recognize Trailer with LED Taillights
  • We have a similar product as the one you referenced, part # TR20141. This product works on most German vehicles that have a hard time detecting trailers with LED taillights. I would normally recommend this for a situation like yours. But we have had feedback with other Land Rover owners who have reported that this product did not work with their trailer with LED taillights. The best recommendation I could make for you would be to replace the LED taillights of your trailer with incandescent...
    view full answer...

  • Running Lights Continually Blowing A Fuse on Trailer
  • Chances are the running lights are drawing too much current. It's possible but unlikely that LED lights would overload the harness. You may simply have more running lights on your trailer than your car tail light circuit can handle. The best way to correct this is to remove some of the running lights or use a powered trailer harness like part # 119179 or part # 119190. I recommend closely examining the running lamp circuit on your trailer, look for any pinched wires or wire with nicked,...
    view full answer...

  • Applying Brakes Causes Taillights of Trailer Towed By 2001 GMC Sierra to Malfunction
  • Things seem to work okay until you apply the vehicle brakes, is that correct? If so, it sounds like a poor ground connection. Make sure the white wire from your trailer connector grounds to the trailer frame (usually on the trailer tongue). Make sure this connection is secure and not corroded. Check the ground for each trailer lamp, as well. Each lamp should ground either through its mounting studs being in direct contact with the trailer frame, or by its own ground wire connected to the...
    view full answer...

  • Troubleshooting Trailer Tail Lights That Blink Together and Shut off When Brakes are Applied
  • The first thing you will want to do is test the 4-way of the tow vehicle that you installed with a circuit tester like part # 3808. See the video I attached to see how this is done. This will tell you if the problem is on the vehicle side or trailer side of the wiring. If the problem is on the tow vehicle then you will want to check the back of the connector for cut or exposed wire that could be causing a short and fix as necessary. If the problem appears to be on the trailer the...
    view full answer...

  • Tracking Down Possible Poor Ground Connection on Travel Trailer
  • What you're describing is the classic symptom of a poor ground connection somewhere in your trailer lighting system. When all the functions are being used, you're drawing maximum amperage through the system, which is when a ground problem will manifest itself. Trace the white ground wire back from the trailer connector. The wire will usually ground to the trailer frame somewhere on the trailer tongue. Make sure this connection is secure and not corroded. Each trailer lamp will also have...
    view full answer...

  • Troubleshooting Blinking LED Trailer Lights with 2012 Range Rover Westminister Tow Vehicle
  • When most vehicles have a difficult time detecting a trailer being connected that has LED taillights we recommend the part # TR20141 that you have referenced. However, we have had several customers try this product on Range Rovers and reported that this did not fix the problem, or in other situations cause fuses to blow. In light of that, your best option would be to replace the LED lights on your trailer with incandescents. To see all of the incandescent trailer lights we offer check...
    view full answer...

  • Electric Brakes Not Working when with Factory Brake Controller on 2013 Silverado and 2014 Yukon
  • Since we know that the trailer brakes do work since they work with your 2011 Ford F-150, the issue must be with the factory brake controllers in the 2013 Silverado and 2014 GMC Yukon XL Denali. The fact that they are GM vehicles is a clue. Sometimes, for whatever reason, GM will not make the tow package fully functional at the factory. You would have to make some connections under the hood. Even though I have not heard of this being an issue on models with factory installed brake controllers,...
    view full answer...

  • When Trailer Connected to 2002 Ford F-350 Trailer Lights Do Not Work
  • This sounds partially like a ground issue. Ground problems normally show up when there is more draw on a system such as when you have the running lights on and then use another function like a turn signal or brake light. Make sure that the vehicle side and trailer side connectors are clean and free of corrosion inside and out. The main connector grounds should be attached to clean and corrosion free bare metal surfaces. Even if the pins in the connectors are clean, corrosion can build...
    view full answer...

  • No Trailer Brake Signal on Factory 7-Way Using Prodigy P2 Brake Controller on 2003 F-250
  • Given the 11-year-old age of your vehicle (and presumably its 7-way factory-installed trailer connector) the issue you are having with no brake signal at the brake circuit pin on the 7-way could be a result of a corroded or damaged 7-way. You can use # HM40975 as a replacement for a factory 7-way. First I suggest you carefully inspect both sides of the F-250's 7-way looking for any signs of damaged wire, worn insulation or even slight greenish or whitish discoloration. Corrosion does...
    view full answer...

  • Troubleshooting a Factory Brake Controller in a 2007 Ford F250 that Shows No Trailer Connection
  • Most likely your problem is corrosion on the brake output circuit of the 7-way. I would inspect the 7-way on both your trailer and 2007 Ford F250 and clean the pins as necessary. I also attached an FAQ article on troubleshooting brake controller installs for you to check out as well. You also can replace your factory brake controller if you like also. For more info on that check out the FAQ article I attached to the right. For a brake controller I would recommend the Prodigy P2 Brake...
    view full answer...

  • Troubleshooting Running Lights on 2010 Palomino Sabre 5th Wheel Trailer
  • There are several potential causes for the lighting malfunction on your trailer, ranging from bad bulbs in the specific fixtures to damaged wiring within the trailer frame to a weak ground wire connection. You can do some simple tests to determine where the issue may be. If you have a spare 12V battery you can try applying power directly from the battery to the problem lights' contacts. If they work when powered directly then you know the issue is somewhere upstream within the trailer...
    view full answer...

  • Left Turn Signal on Trailer Will Not Blink but All Other Lights Work
  • This sounds like a ground issue. Ground problems normally show up when there is more draw on a system such as when you have the running lights on and then use another function like a turn signal or brake light. Make sure that the vehicle side and trailer side connectors are clean and free of corrosion inside and out. The main connector grounds should be attached to clean and corrosion free bare metal surfaces. The light grounds should also be attached to clean and corrosion free bare...
    view full answer...

  • Troubleshooting Non-Functioning 7-Way on Motorhome
  • Since your wiring was accidentally pulled out of the motor home socket, and since you have already checked your fuses and relays, it could be that the socket itself or its connector was damaged. We do offer a replacement 7-way for the F-450 SD and that is part # 20119 from TowReady. This OEM replacement harness installs using a round U.S. Car connector and provides both 4-pole and 7-way connection points.
    view full answer...

  • Trailer Brakes Do Not Work When Using 7-Way to 6-Way Adapter with a 2010 Chevy Silverado
  • The problem that you are experiencing is likely happening because there are 2 different ways to wire a 6-Way trailer connector. The brake output pin will wither be the center pin or it will be in the 2 oclock position, if looking at the face of the trailer side connector. Which ever one that it is, the other one would be the 12 volt circuit. Normally when this happens the trailer brakes will immediately lock up. But it is possible because you have a Chevy truck that the 12 volt circuit...
    view full answer...

  • Troubleshooting Camper Trailer Taillights Not Working
  • First let's figure out if the problem is on the trailer or the tow vehicle side of the wiring. You will need to use a circuit tester like our part # 3808 to test the functions of the trailer wiring harness on your 2009 Ford F250. Check out the video I attached to the right to see how this is done. While your testing the running light pin on your tow vehicle make sure the connector is clean and free of corrosion. Do the same for the trailer's connector. If the problem is on the tow vehicle...
    view full answer...

  • How to Test the Functions of Trailer Tail Light Circuits
  • The easiest way to test the functions of the taillight wiring on a trailer is to use a jumper wire. You will touch one end of the jumper wire to the positive post of a 12 volt vehicle battery and then touch the other end of the wire to all of the different wires to see what circuits illuminate. The other option would be to trace the wires back to see where they terminate.
    view full answer...

  • Troubleshooting Trailer Lights After Installing Hopkins Adapter 4 Pole to 7 Pole and 4 Pole # 37185
  • You will want to test the Escape's 4-pole wiring, that connects to the Hopkins Adapter # 37185, to determine if the vehicle is properly sending the lighting signals to the adapter. Use a circuit tester like # 40376 on each of the wires on the vehicle's 4-pole harness. Ground your tester to the exposed pin for the white ground wire. The yellow wire should carry left turn and stop light signals; the green wire should carry right turn and stop light signals; the brown wire should carry a running...
    view full answer...

  • Troubleshooting Faint Taillight Functions on a Horse Trailer
  • A couple of things could be what's going on. First thing I would do is inspect both trailer connectors on your truck and trailer. Clean off the connection points as it sounds like you have some corrosion that is preventing the connection from being made. The next place to look is the grounds of the trailer. Each light assembly should be grounded to a clean metal surface. A lot of assemblies ground through the mounting hardware so make sure they are attached to a clean metal surface....
    view full answer...

  • Trailer Lights Go Out when Vehicle Brake Pedal Is Applied and Both Turn Signals Blink
  • This sounds like a ground problem. The first thing you should know is that testing the trailer with another vehicle is not a fool-proof way of determining wiring issues on the trailer. The other vehicle may have a wiring system that can overcome the ground problems that the intended vehicle cannot. Ground problems normally show up when there is more draw on a system such as when you have the running lights on and then use another function like a turn signal or brake light. Make sure...
    view full answer...

  • Troubleshooting an Electric Trailer Jack that Doesn't Function on a 2005 Chevy Silverado
  • First thing you will want to do is use a circuit tester like our part # 3808 to test the 12-volt accessory pin on the 7-way of your 2005 Chevy Z71. You should see 12-volts there. This pin will be the 1:00 position of the connector. If there is no voltage there then you will need to check under the hood of your truck to make sure all of the necessary tow package connections are being made on the fuse panel of your truck. This is most likely the problem as one of the connections that gets...
    view full answer...

  • Troubleshooting Trailer Lights that Stop Functioning When Running Lights Come On
  • Sounds like your trailer lights have weak grounds. The behavior you described is textbook insufficient grounding. What you will want to do is check the grounds for the trailer taillights, make sure they are attached to a clean metal surface. Also, make sure the main ground from the trailer's wiring connector is attached to a clean metal surface on your trailer frame. I attached an FAQ article on diagnosing 4-way installs for you to check out plus an FAQ article on trailer wiring.
    view full answer...

  • Trailer Lights Do Not Work when Connected to Truck But Work with AC to DC Converter
  • First, when lights work intermittently that is an indication of a ground problem. It could also be a loose connection somewhere or a dirty/corroded trailer connector. Ground problems normally show up when there is more draw on a system such as when you have the running lights on and then use another function like a turn signal or brake light. Make sure that the vehicle side and trailer side connectors are clean and free of corrosion inside and out. The main connector grounds should...
    view full answer...










Stay Connected


Subscribe to email newsletter

Email  

privacy - we don't send unsolicited email






etrailer.com reviewsetrailer.com reviews

All images, layout and content copyright etrailer.com