A circuit tester that plugs into the 7-way trailer connector on the vehicle and emulates a trailer. The lights let you know what functions (brake, turn, tail, stop, reverse and 12V) are working properly and what functions are not. Lowest Prices for the best Wiring from Tow Ready. 7 Way Trailer Connector Vehicle Tester part number TR20117 can be ordered online at etrailer.com or call 800-298-8924 for expert service.
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Wiring > Tools for Wiring > Testers > Circuit Tester > Tow Ready

7 Way Trailer Connector Vehicle Tester

Tow Ready Wiring

(63 reviews)

Code:   TR20117



Shipping Special

Shipping Weight: 0.35 pounds


Tow Ready Wiring - TR20117

A circuit tester that plugs into the 7-way trailer connector on the vehicle and emulates a trailer. The lights let you know what functions (brake, turn, tail, stop, reverse and 12V) are working properly and what functions are not.


  • 7-way circuit tester
  • 12V power
  • Function Codes:
    • BU: back up or reverse circuit center pole
    • RT: right turn/brake
    • TM: taillights
    • LT: left turn/brake
    • BK: Brake controller output
    • 12V: 12-volt power feed

Note: Designed for use with Tekonsha and Draw-Tite aftermarket brake controllers and Ford OEM brake controllers. May or May not work with other manufacturers brake controllers.

20117 Tow Ready 7 Way Trailer Connector Vehicle Tester

Replaces 18179

Video of 7 Way Trailer Connector Vehicle Tester

Videos are provided as a guide only. Refer to manufacturer
installation instructions and specs for complete information.

Video Transcript for Tow Ready 7 Way Trailer Connector Vehicle Tester Review

Today we're going to show you the 7-way trailer connector vehicle tester, part number TR20117 from Tow Ready. All right, this is a handy device to keep with your vehicle. You can use this to test your vehicle any time. For instance, you have a problem with your trailer, you're not too sure where to start. Go ahead and use this tool in your 7-pole connector in your truck to verify your truck is working fine, then you know it's on the trailer side. Now the indicators are going to be these LEDs right here.

They have their own markings. TM for the running light circuit or trailer marker lights. LT for left turn, twelve volt power supply, so something in your trailer may require twelve volts like the interior lights or something like that. BK for the output from your brake controller. BU for your backup lights, reverse lights, and RT for your right turn signal.

And bye the way, with the brake controller this test was actually designed for use with Draw-Tite or Tekonsha brake controllers, and also the Ford OEM brake controller as well. This may or may not work with other brands of brake controllers out there. Let's go ahead and plug it into our truck here and show how it works. Just like any other 7-pole connector, you just push it in place. Make sure it's fully installed. You can see where I already have a couple of lights showing up.

One's going to be four a twelve volt power supply, and one's going to be for a brake controller outlet. All right, in this case our brake controller sends out a small trace current to look for a completed circuit, so that's why we have it lit up already and we're not even using our controller. That's perfectly normal. Okay Let's go ahead and try the running light circuit next. All right, that's our indication for the running lights.

Let's try our left turn signal. Okay. Now let's try our right turn signal. Okay. Let's look for our brake signal, which would be indication on our left turn and right turn signals. Okay. All right, and now we'll go ahead and try our back up lights, which we will put the vehicle in reverse. That will finish it for part number TR20117, the 7-way trailer connector vehicle tester from Tow Ready.

Customer Reviews

7 Way Trailer Connector Vehicle Tester - TR20117

Average Customer Rating:  4.6 out of 5 stars   (63 Customer Reviews)

A circuit tester that plugs into the 7-way trailer connector on the vehicle and emulates a trailer. The lights let you know what functions (brake, turn, tail, stop, reverse and 12V) are working properly and what functions are not.

- TR20117

by: Bill_OldGuy08/10/2013

The product wasn’t very useful for my application. I have an OME installed trailer kit which has an isolation box between the vehicle and the trailer connector. I could tell the turn signals worked and that the electric break controller was working but everything else caused the LEDs to glow with what looks like high impedance semiconductor leakage regardless of whether the light was off or on. There just not enough load in the tester to bleed off stray voltage. I went old school with two clip leads, a 12 v bulb and an ice pick to verify that the vehicle was functioning properly. I have no confidence in what the tester indicates when the LED glow and whether the trailer connector is working or not. This will probable work if you only have copper between your vehicle lights and your trailer connector. 94367

- TR20117

by: Roadkill07/09/2013

This 7 Way Trailer Connector Tester does Exactly what I was hoping it would do. It clearly indicates which electrical function is working on the Vehicle. I rated this "Very Good" rather than "Excellent" for ONLY one reason. When looking at the indicator lights on the tester they DO show which function is operating. What "might" be a little confusing to some is the fact that the indicator lights to not match exactly to the location of each tab inside the plug mounted on the Vehicle. Had the indicator lights on this tester match each location inside the plug I would absolutely have given this an "Excellent" rating. I still feel this is a Very Good tool for testing the wiring to insure each function is working properly. 88545

- TR20117

by: Thomas DiBartolomeo11/05/2013

The product is good with the STANDERD trailer hook up, But it does NOT work on my 2013 chevrolet 2500 inergrated braking towing controller ( IBTC ) When you hook the tester to the plug and apply the trailer brakes all you see is one Blink on the tester and then it goes back out. Now I took my New 2013 truck to the dealer and they checked the braking system and found Nothing wrong and said it was OK . Please test this on the 2013 chevrolet 2500 ( IBTC) and you will see what I mean and please if there is anything that I have done wrong please contact me because this tester does NOT work on my NEW truck .....Please respond ! 106348

- TR20117

by: Michele G.02/04/2015

This item was extremely helpful in my recent purchase of a tow vehicle. I had been looking at used trucks and brought this to determine if the wiring in the tow package was in working order - come to find out the 12v light wasn't coming on so I was able to tell the dealership I'd buy the truck if they'd be sure to fix it. Turns out it was only a fuse so an easy fix. I believe this will come in handy from time to time if I find anything not working on my trailer (will know if it's on the truck end or on the trailer). Thanks eTrailer for a FAST delivery and great product. 172361

- TR20117

by: John G.10/24/2013

Great tester 105004


This tester is fantastic!

John G - 10/24/2014


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by: OK04/30/2015

At first I was very disappointed in this product. I put it in my 7-way plug and the LEDs were facing my vehicle so I couldn't see them at all. Turns out you can loosen a set screw and rotate the LEDs to point in a different direction. Once the happened it was better. I found the LEDs were hard to read in the sunlight but it did its job. Also the pulls tabs on each side are so big that it makes putting the tester into the plug difficult in certain situations where there is not very much space like on my minivan. 188960

- TR20117

by: Mike s Lawn Service02/10/2014

With this product I was able to narrow down my electrical problem to my truck and not the trailer, and by knowing that the problem was the truck I was able to narrow down the problem down to a 1 foot long piece of wire behind the tail lights but before the outlet. I did all this by simply looking at the tester and following the wires with my eyes. This tester saved me several hours of time, money in parts I didn't need and not to mention the immeasurable frustration caused by trying to find electrical wiring problems. 116192

- TR20117

by: Leon C.05/13/2014

I received my 7 way tester fast , and it was packaged well. it came in handy to test my trucks plug to find out it wasn`t getting any power. when I found out what the problem was it was real easy to look at the lights on the tester to see they were all working rather than hooking the trailer up and keep running back to the trailer to check if they were working. 130500

- TR20117

by: James Norton12/27/2012

I had used the product before. While performing the testying of my camper/truck lights several family members were amazed at how easy this product was to use for trouble shooting problems. As a result, they asked me if I would get them that for Christmas. Personaly, I couldn't have been more pleased with the product. 62060

- TR20117

by: Kenneth R01/12/2011

Great Service My order was filledfast, with great followup and tracking. I'd have no problems ordering from you again. I used the truck, trailer plug tester at a local RV dealer and just had to have one. TThis way I can test all my lights, brakes before pulling the trailer from the shed.Thanks K.R. 5398

- TR20117

by: Alex02/12/2015

Works as expected. Would like more clear marking as to what circuit is energised. Used it to check vehicle connections that mechanic said were working. Guess what they were not, no signals no brake lights and no running lights. Going to take it with to show him when i return. 173485

- TR20117

by: joel b09/15/2013

Great product. Figured out the problem I was having in minutes instead of going back and forth with the trailer. I do think the lights could be more obvious. Just show one light if working. Instruction sheet wasn't included. Support got it to me immediately though. 99986

- TR20117

by: Speedy05/12/2011

This 7 way vehicle connection tester works great. I'm able to trace any poor or bad connections associated with my truck's trailer harness quickly. Low cost and quality design makes it a great tool to leave in the trucks toolbox in case I have future connection issues. 13733

- TR20117

by: Dusty R.01/14/2011

Fast and what I needed The product arrived super fast and was exactly what I needed to fix lighting issues on my trailer. No longer did I have to wire and rewire the connector to find the right places for the wire. Cut the working time down drastically. 5471

- TR20117

by: Rider09/18/2012

The tester works fine, but the LED lights on the tester are arranged in a confusing manner, the lettering indicating which LED light is on are very small, but overall, it will be a good tool to help test the towing vehicle electrical trailer circuits. 55071

- TR20117

by: David03/05/2013

Tester made all the differents in the world, my wireing harness had been cannibilized, so I needed to make a good water tight connection under my truck. The juction boxes were the ticket, making a professional job oit of it. Thanks etrailer 68853

- TR20117

by: Ed B.05/11/2011

I have only used my tester twice, it worked great! My connector on my truck was hooked up right. My bosses was not. It was nice to be able to just plug it in w/out having to hook up a trailer. It is a great compliment to anyones toolbox. 13556

- TR20117

by: J-E12/14/2013

This vehicle wiring 7-way tester arrived in three days and works perfectly. The circuits are clearly marked and the LEDs are easy to see in the bright sunlight. Thanks Patrick! Excellent product and service! J-E 110125

- TR20117

by: PAMike06/28/2012

Helpful. However, it does not put a load on the signals, so if you have a weak 12-volt or ground connection to your trailer-light signal converter, it will still indicate that the system is working properly. 45992

- TR20117

by: Richard A04/03/2014

Used for monitoring five church vans to insure proper working order before leaving on youth trips and mission trips. Really appreciate the the item when having no second person to assist. 123524

- TR20117

by: Phil07/22/2015

This thing is easy to use and works well. The only problem is that the LED indicators draw much less current than my trade Lights which has made diagnosing my specific problem difficult. 213620

- TR20117

by: charles hill12/21/2010

tester this is a dreat product to check your ride to see if everything is working right. it checkes every funtion,you do have to have two people to check or do a lot of walking, 4409

- TR20117

by: MAX02/04/2013


- TR20117

by: Todd R11/05/2013

Works good. I have a brake controller though and it wouldn't like up. I suspect its a problem with the type of controller I have. Everything else works great. 106388

- TR20117

by: David B06/23/2012

Great tester. Great price. Unfortunately, now I have to find the problem......Well worth the price just to relieve the aggravation of my old tester. 45366

- TR20117

by: Bob02/04/2012

Thank You for the Fast service and Great Deal THis is a real time saver as I had a problem and the plug helped me fix it "GREAT PRODUCT" Thanks 31076

- TR20117

by: CRAME10/22/2013

Item was shipped and arrived in minimum time and works as advertised, I'm very happy with quality and functionality of this tester. 104747

- TR20117

by: Robert04/06/2013

Just what the doctor order, work's great and easy to use. Thanks for your help and your tect's help. Best regards; Robert Brown 74507

- TR20117

by: SA11/01/2012

Works well. Brake light is dim when brakes are applied, but I assume that is due to the controller. No directions are included! 58613

- TR20117

by: Joey12/04/2014

Cheap easy way to test the wiring of the truck plug. Must have for any business which has a fleet of trucks. 163377

- TR20117

by: David B.03/31/2015

One of those neat tool for the tool box. This way you know if you got the vehicle wired correctly 181920

- TR20117

by: Tony D.11/10/2014

Great web site, great service, fast delivery worked as described highly recommend etrailer ! 160192

- TR20117

by: John C.04/29/2015

It worked great, I didn't know if I had a problem with my truck or trailer, but now I know. 188808

- TR20117

by: Henchman07/20/2015

Product was very easy to use and helpful in checking out my electrical trailer connection. 213244

- TR20117

by: John E.09/10/2015

Great function and fit. I'll keep this in the glove box in case there are any issues. 224842

- TR20117

by: AD01/03/2013

The item is just what I needed. And shipping was fast too !!! Thanks etrailer.com 62417

- TR20117

by: Mike Lyon10/13/2014

Great product -- makes checking the vehicle side wiring very easy 155753

- TR20117

by: Mike M05/12/2011

Works nicely, just as described. Great tool to keep in the toolbox. 13731

- TR20117

by: Ross B.04/21/2011

easy to use, the lights make it easy to identify problem areas 12161

- TR20117

by: Dan T09/13/2012

WOW....can you say fast service(within 2 days) Thank you 54642

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by: Dave S.06/03/2012

Works as advertised. Etrailer service and prices excellent 42523

- TR20117

by: Archie L.09/28/2011

This product works well I would recomend this to a freind. 24814

- TR20117

by: Billy C.06/09/2015

works well was satisfied with Item and on time delivery. 202044

- TR20117

by: tom s07/04/2014

Great product and fast response from et railer. 139161

- TR20117

by: tom s07/04/2014

Great product and fast response from et railer. 139160

- TR20117

by: Jim W.08/12/2014

I am very pleased wioth my purvhase. Thanks again. 146154

- TR20117

by: Joe y06/05/2015

Works as advertised for good price shipping fast 200965

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by: Chuck08/30/2015

Simple, Easy, you have power and lights or Not 222875

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by: Rob O.03/09/2012

Great little device, saves time & guess ing. 33449

- TR20117

by: edcam04/15/2014

very nice product to carry in your truck 125200

Show More Reviews

Ask the Experts about this Tow Ready Wiring
Do you have a question about this Wiring?

  • No Power To The 12 Volt Terminal On The 7-Way Vehicle End Connector
  • The 12 volt power lead on the 7-Way will be the terminal that supplies power for trailer interior lights, trailer battery charging. If you are looking at the 7-Way on your vehicle the 12 volt power terminal is the #4 (black) pin located at the 1:00 position. It is normally either a black or red wire. See the picture to the right of a typical 7-Way and it will show the terminal locations and what each function is. I am including a video link on how to wire a 7-Way vehicle end connector. If...
    view full answer...

  • Trailer Lights Stay on Once Vehicle Ignition is Shut Off
  • I suspect your problem is caused by a damaged or corroded trailer connector. Take a look at your trailer connectors, both the socket on your truck as well as the plug on the trailer. Look for green or white corrosion on the pins or sockets of the connectors. If corrosion is visible, there is a strong possibility that the corrosion has spread to the interior of the connector. The terminals that each individual circuit connects to are very close together, if corrosion builds up on the...
    view full answer...

  • Comparison of the Tekonsha 7-Way Trailer Emulator # 6562 and the Tow Ready 7 Way Tester TR20117
  • Yes, both the Tekonsha 7-Way Trailer Emulator, item # 6562, and the Tow Ready 7 Way Tester, item # TR20117, will test the function of the left turn and stop, right turn and stop, tail/marker lights, 12 volt power, electric brake, and the backup circuit in the 7-Way vehicle side connector. With both testers, the electric brake test will tell you that the circuit is supplying power for the trailer brakes at the plug, but will not check for actual, or correct, voltage. A multi-meter, item...
    view full answer...

  • Flashing Trailer Lights with a 2008 Mercedes GL450 with Factory Tow Package
  • It sounds as if you have the trailer ruled out as the problem. I would recommend you check the ground connection on the trailer, to make sure it is connected securely to clean metal, so you eliminate that as a potential problem. I would then look at the connector on the vehicle. Try using a tester, part # TR20117 to check if all circuits are functioning. If you find a problem at the connector, since the tow package is factory, not aftermarket, I would recommend you check with your Mercedes...
    view full answer...

  • Pairing Tekonsha RF # 90250 to 2011 Mercedes Benz GL450
  • The Prodigy RF is an excellent piece of equipment, but in order to synchronize the power unit to the hand held remote, the pairing instructions mentioned in the owners manual need to be followed to the letter. First, use a circuit tester like part # 40376 on the 12-volt power supply pin on your 7-way to ensure it is powered up. The pin will be in the 1:00 position in the connector. If this pin is not active, the controller will not pair to the remote. Begin by hitching the trailer...
    view full answer...

  • Difficulty Pairing Tekonsha Prodigy RF # 90250 Brake Controller with 2012 BMW X5
  • The manufacturer of the Prodigy RF, Tekonsha, tells us that many European SUVs (including your X5) will throw a wrench into the works during the pairing process. These vehicles have a system that senses if a bulb on the vehicle or the trailer is burned out. This sensor works by sending a test pulse of voltage through the trailer connector every so often. During the pairing process, this can confuse the RF unit into thinking that the brake pedal is being pressed at the wrong time, which...
    view full answer...

  • 2006 Ford F350 With OEM Brake Controller Not Reading Trailer
  • When using the wiring diagrams you speak of, it is important to remember that wire colors can vary, and it is best to wire by function rather than wire color. The easiest way to determine which wiring circuit preforms which function is to use a car battery, ground the white wire from the trailer connector lead to the negative battery terminal, and apply 12 volts to each of the remaining circuits in order to determine their function. By going this route, you can be sure that the connector...
    view full answer...

  • Will Tow Ready 7 Way Connector Vehicle Tester # TR20117 Test If a Brake Controller is Working
  • The Tow Ready 7 Way Trailer Connector Vehicle Tester, part # TR20117, will test the 7-Way connector on your 2008 Ford Super Duty to make sure all the functions are working and the terminals are wired properly. It will tell you if you have 12 volt power and brake lights at the 7-Way which is needed for a brake controller. It does not test to tell if your brake controller is working or not. You will need to test your brake controller separately. I am including a link to a video that will...
    view full answer...

  • Using Tow Ready Trailer Connector Tester Part # TR20117 to Diagnose OEM Brake Controller Problem
  • The Tow Ready 7-Way Connector Tester will draw enough power to simulate a trailer. Another option would be to try a different trailer on your truck. If the same problems appear, you will have eliminated the trailer as being the problem. I would also recommend you check the trailer connector on the vehicle and the trailer, making sure neither is damaged or corroded. If you can see any white or green corrosion on the pins or sockets of the connectors, there is a chance that the corrosion...
    view full answer...

  • No 12 Volt Power on 7-Way on a 2012 GMC Sierra Denali
  • Most likely you need to make some connections under the hood of your truck to make the 7-Way fully functional. Under the hood, driver side, near the windshield you will find the power distribution box, There should be wires attached to the 2 studs on the forward most studs. If there are not you will need to locate them and attach them. The battery charge wire should be located under the master cylinder/brake booster assembly. Attach it to the smaller stud on the front of the power distribution...
    view full answer...

  • Troubleshooting Left Turn Signal Staying Hot on a 2013 GMC 3500HD Towing a Trailer
  • If you used a 7-way circuit tester like our 7 Way Trailer Connector Vehicle Tester # TR20117 and the LT circuit stayed lit that would indicate that there is voltage on this circuit at all times which means something is shorting out onto this circuit. Due to the fact that it is hot all the time it would seem that it is the 12 volt power circuit that is shorting to the left turn/brake circuit. I suspect you have a 7-way round connector since on these style connector the left turn and 12...
    view full answer...

  • Availability of Tester for Round 7-way Vehicle Socket
  • The part you referenced, Pilot 7 Pole to 4 Pole and 5 Pole Adapter/Tester # TC-701, does provide a testing function as well as adapt the 7-way RV-style socket on a tow vehicle to a 4- and 5-pole socket. If you do not need to change the connector type and just want to be able to test, you can instead use part # TR20117 from TowReady. The linked video illustrates. The tester plugs into the 7-way trailer connector on the vehicle and emulates a trailer. The LED indicator lights let you know...
    view full answer...

  • Trouble Shooting a Primus Brake Controller on a 2003 Chevrolet 2500 HD
  • Often times if break-away kits are not wired properly, they will cause problems with a brake controller. The first thing to do would be to make sure there is not a problem on the vehicle. Disconnect the trailer and turn on the truck. You should see one dot on the display, in the center, indicating that the brake control has power and is active, but there is no trailer connected. When you apply the manual lever with no trailer connected the display should read n.c.. If all this works...
    view full answer...

  • Troubleshooting Trailer Brakes Locking Up When Lights are On and no 12 Volt Circuit Voltage
  • It sounds like somehow the running light circuit got wired to the brake output circuit of the 7-way at the rear of your vehicle, and that is why when the lights are on the brakes lock up. I would check the wiring of the brake output circuit of your 7-way, I would be willing to bet there are two wires run to it and one of them is the running light circuit that should be run to the correct terminal of your 7-way. Check out the FAQ article I attached on trailer wiring.
    view full answer...

  • Trouble Shooting Inoperable Electric Brakes on a 10K Trailer
  • Since you have fresh parts in the hubs and provided they are installed properly, I suspect there is a problem somewhere in the wiring or with the brake controller installation and set up. You will need to check the whole system, step by step, to find out where the problem is. If you have used your truck successfully with other trailer brake equipped trailers, then the brake controller and vehicle wiring should be fine and you can skip the first 2 steps. If you tried it on different vehicles...
    view full answer...

  • Can 7-Way Trailer Connector Vehicle Tester be Used on a 2007 Chevy Silverado
  • Yes, you can use 7-Way vehicle side trailer connector tester # TR20117 on any RV style 7-Way trailer connector, also called a 7-Way blade style connector, including the one on your 2007 Chevy Silverado!
    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...

  • Fuse and Relay Locations for 7-Way Connector 12 Volt Circuit on a 2002 Ford F-350
  • The fuse used for the 12 volt circuit on a 7-Way trailer connector on a 2002 Ford F-350 is the battery charge or trailer battery charge fuse. On your truck it is location 115. There is also a relay for this circuit in location 305.
    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...
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  • Troubleshooting 12 Volt Power Circuit not Functioning on 7-Way After Re-Wire
  • There could be corrosion or dirt inside your 7-way that needs to be cleaned out before all of the circuits of the 7-way will activate. That's the most common reason circuits on a 7-way won't function properly. You can test this easily by using a circuit tester like our part # 3808 to test the wires that feed into the 7-way on the circuits that aren't functioning. If the wires have voltage but not the pins the problem is corrosion or dirt on the inside or outside of the connector. Also,...
    view full answer...

  • Troubleshooting a Brake Controller that Only Activates with Manual Override Lever
  • If a brake controller only activates with the manual override lever one of two things are going on. Either the controller is not properly attached to the right stop light circuit, or the controller itself is bad. You will want to use a circuit tester like part # 3808 to test the circuit that the red wire of the controller is attached to on your 2009 Ford F450. It will need to have voltage when the brakes are applied and none when released. If you verify that the controller is attached...
    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...
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  • Tips on Finding the Fuse for 12 Volt Circuit on a 2007 Winnebago Trailer Connector
  • The hard way to find a fuse is to trace a wire. This is nearly impossible if the wire disappears into the vehicle where you can't follow it. The manual may not call it something that is obvious. Trailer tow, auxiliary power, or any number of phrases could be used. It could also be located in the cab or under the hood. If the manual is no help most power distribution box lids and panel lids have a legend on them that might be more helpful. If you just cannot find it at all you can bypass...
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  • 7-Way Trailer Connector 12 Volt Circuit has Power All the Time
  • The 12 volt circuit on a 7-Way that was hardwired into a vehicle is going to have power all the time. Provided nothing is plugged into the 7-Way that draws power from the 12 volt circuit then it would not be a problem. The little LED light would take months to drain a vehicle battery if you were to let it sit all that time and never start the vehicle. But there is a way that you can shut off power to the 12 volt circuit when the vehicle is off. You would need battery isolation solenoid...
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  • 7-Way Tester Recommendation for a Land Rover with 7-Way and P3 Brake Controller
  • Yes, we do offer a 7-way tester that will allow you to plug into the 7-way at the rear of your Land Rover to test all of the functions. For that you would want the part # TR20117. Check out the review video I attached for more information.
    view full answer...

  • Troubleshooting Fuses Blowing after Replacing Trailer 4-way with 7-Way
  • Sounds like there is a short on the vehicle side of the trailer wiring. Check the wiring of the connector on your tow vehicle to see if there is any cut or exposed wire and fix as necessary. The short will be on the 7-way side of the wiring of your tow vehicle. What circuit has the 10 amp fuse that is blowing? That will be a good indicator what circuit has the short. I attached a couple trailer wiring FAQ articles for you to check out as well.
    view full answer...

  • Should Trailer Wiring Have the Running Light Circuit Always Activated
  • The only time the running light circuit of trailer wiring should be on is when the headlights or running lights of the vehicle are on. You might have a shorted trailer wiring converter box or a bad relay if the trailer wiring is factory. I attached a help article on troubleshooting trailer wiring installs for you to check out as well.
    view full answer...

  • Lost Reverse Light Signal on a F-350 Dump Body Truck and Trailer
  • Is reverse light function dead at the 7-Way connector on the F-350 or you just not getting reverse lights on the trailer anymore? Check with the 7-Way connector on the truck with either a circuit tester like part # 3808 or a 7-Way tester like part # TR20117. If you have the reverse function at the truck connector then the problem is on the trailer. If not, then the problem is probably on the truck. If the problem is on the truck, trace wiring and check for nicks or fraying connections....
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  • 2007.5 GMC 3500 Integrated Brake Controller Not Working
  • There are a couple of things you can do to try and troubleshoot your GMC 3500. First I recommend making sure that the emulator you are using is compatible with GM trucks. The emulator that you mentioned # TR20117 works only with Ford OEM brake controllers and Tekonsha and Draw-Tite aftermarket controllers. Some times, the LED lights on the emulators don't have enough draw to fully trigger the brake controller. A circuit tester with an incandescent bulb, like # 40376, will have enough...
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  • What Fuses to Install After Mounting Pollak Twist-in 7-Pole Socket # PK11916 in 2012 GMC Sierra
  • Installation of the Pollak Twist-in 7-Pole Socket # PK11916 is shown in the linked video; this video features the same model year Sierra as yours. In order to activate the tow package wiring you may need to install some fuses in the power distribution box within the engine compartment. Open the cover and check the legend on the lid for any empty fuse locations labeled trailer or tow. If fuses are not already installed in these receptacles you can insert the appropriate values as indicated...
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Info for this part was:

Installed by:
Joe V

Expert Research:
Michael L

Video by:
Andrew K

Expert Research:
Robert G

Expert Research:
Michael H

Expert Research:
Jeff D

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Jameson C

Video Edited:
Jacob T

Expert Research:
Adam R

Updated by:
Laura H

Photos by:
Amber A

Photos by:
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