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Pollak 7-Way to RV Socket LED Circuit Tester - Vehicle End

Pollak 7-Way to RV Socket LED Circuit Tester - Vehicle End

Item # PK12741
Our Price: $26.93
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This circuit tester plugs into the 7-way connector on your truck. LED lights indicate which functions (brake, turn, tail, stop, reverse and 12V) are properly working. 1-800-940-8924 to order Pollak electrical tools part number PK12741 or order online at Free expert support on all Pollak products. Great prices and Fastest Shipping for Pollak 7-Way to RV Socket LED Circuit Tester - Vehicle End. Electrical Tools reviews from real customers.
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  • Reviews (137)
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  • Videos (2)
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Pollak Electrical Tools - PK12741

  • Testers
  • Circuit Tester
  • Tow Function Tester
  • Pollak
  • Black

This circuit tester plugs into the 7-way connector on your truck. LED lights indicate which functions (brake, turn, tail, stop, reverse and 12V) are properly working.


  • 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

12-741E Pollak 7 Way to RV Socket LED Circuit Tester

Compare to Tow Ready TR20117

Replaces Pollak 12-741EV

Video of Pollak 7-Way to RV Socket LED Circuit Tester - Vehicle End

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

Video Transcript for Pollak 7-Way to RV Socket LED Circuit Tester Review

Hey everybody, Ryan here at etrailer. Today we're gonna be checking out the Pollak seven-way circuit tester. What this tool's gonna do is allow you to check the functions of your vehicle's seven-way. So this is a bladed style, so extremely common. You see these on RVs and pickup trucks and SUVs like what we have here today. And it's gonna check all of those lighting functions.

So we're gonna have left turn, TM for taillights, RT for right turn. This one down here will be our 12 volt auxiliary power. BK will check our brake controller output and BU will be back up or reverse lights. And then of course whenever you hit the brakes both of the turn signal lights should illuminate allowing or letting us know our brake signals work. Why don't we get right into it though and check our vehicle's trailer functions.

Make sure the seven way's working. So this will just plug right into your seven way and if the lights illuminate, we know that circuit is working. So right away our 12 volt power illuminated. So we know that's good, but we'll go ahead, get inside the vehicle here and run through the rest of our functions. We'll go ahead and turn on our taillights.

I'll go ahead and turn 'em off and now we'll try our left turn signal, our right turn signal, we'll hit our brakes and if you had a brake controller you would apply power to it to test that function. In our case, our vehicle doesn't have one so we don't have to worry about it but it'll work the same as all the other signals if you do. And then I'll have to start up the truck here, (engine ignites) put it in reverse and test out that signal. A very simple tool and is something good to have especially if you pull a lot of trailers or tow often. And this is just gonna help you isolate a problem.

If you do happen to have one, which it seems like it never fails, you go to hook up to a trailer it's been sitting for a while, seems like you end up running into issues with the light. So instead of wondering if it's your vehicle side or the trailer side, this will help you determine that. So let's just say for example you hook up to your trailer, everything's working other than say, the left turn and brake light signal. What you could do at that point is take your tester, plug it in. If it's working on your vehicle side you need to focus your efforts on the trailer 'cause that's likely where the issue is gonna lie. But let's say you plug this in and it's not working on your vehicles side, that's gonna let you know that something's going on with the truck, right Probably a popped fuse or something along those lines. So you can get that sorted first, hook up to your trailer, test it out, if it's all working like it should, great. If not, chances could be you might have an issue on the truck and the trailer. So it's just one of those things that kind of gets you going in the right direction and makes it a little bit easier to figure out any type of lighting issues that you might run into. Just to do a quick comparison here is a Curt seven-way tester and I really don't have a preference so to speak. it's a pretty simple tool. Either one will work just fine. One thing I did kind of notice with the Curt is that it's a little bit longer and so if I go to plug this into the seven-way, most seven-ways are very similar to this, it comes out a little bit further. So it's a little bit easier to see the lights. Plug this one in, just give you a visual. The Pollak one, not a game changer. But something I did notice, and I will say, with both of these, I've experienced in the past some of these more late model trucks that have factory built-in brake controllers, sometimes a truck is almost too smart and it doesn't recognize these as being a trailer, so to speak. So sometimes if you go to test that function, and that's not the case with every late model truck, just some of 'em that I've ran into. When you go to test that function, sometimes it doesn't really wanna work even though the brake controller is working. Just because the truck's, like I said, almost too smart and realizes this isn't a trailer. But just wanted to mention that in case you run into that issue. But other than that, at the end of the day this is a good tool to have that you can throw in your glove box and could potentially save you some headache whenever you go to hook up to your trailer next time.

Customer Satisfaction Score:

Customer Reviews

Pollak 7-Way to RV Socket LED Circuit Tester - Vehicle End - PK12741

Average Customer Rating:  4.7 out of 5 stars   (137 Customer Reviews)

This circuit tester plugs into the 7-way connector on your truck. LED lights indicate which functions (brake, turn, tail, stop, reverse and 12V) are properly working.


It’s a good tool to have to make sure your vehicle’s trailering lighting system is correct before hooking up to the trailer and hitting the road.


Exactly what I needed for a repair!


great size and easy to use


I bought the 7-way LED circuit tester. I bought a used Class A motor home and have had problems with the 7-way plug on the motor home This will help me resolve the last issue. A few weeks ago I had also purchased the 4-way flat LED tester and now have both in my tool box. Thanks

Gary S.


Great to have in my tool box. I loaned it to a guy in the camp site next to us.It helped him to locate his problem in minutes. GREAT!


Not much to say about a trailer plug tester other than it works just fine
and is as advertised. Shipping was prompt and I was able to solve my neighbors
wiring problem quickly without a hassle.
If I ever need any trailer related parts or ?? You people will be the first that I will



It still works great


There have been several times this tool has helped isolate problems with trailer wiring by insuong tow connector AOK. 5th wheel, horse trailer, flatbed, and touhauler all had either a bad connector, a bad wire, corrosion issue, difficult to isolate but easy to repair. Saved a lot of time.


It works, but one of my vehicles is too smart and it does not output a signal unless it senses a bigger load then these LEDs.


works well. worth the price. you have to make sure you get the correct one. those 7 pins can be wired differently. email them and tell them what vehicle you have. some trailer hitches have the groove on top some on the bottom. if yours is on the bottom you will have to lay on the ground to read it, because the lights will be pointing at the ground. the lights are on the groove side.


Arrived promptly and it worked as expected when I tested it on my tow vehicle. A previous reviewer stated that he wished there was a card that listed what each light tested. It is marked on the plug around the test lights, but the printing is the same color as the plug. That is the only reason that I gave this product 4 stars. I used a paint stick to highlight the markings so that I can read them easily without my glasses.


Super helpful to have one of these testers. I suspected my trailer battery was not getting charged by the tow vehicle, and this tester confirmed the problem was my 12 volt wire is not active. Saved me time as now I know where to go next for resolution. Also easily can confirm my truck's trailer plug works without having to hitch up. Totally worth it in time saved.


The tester plugs in easily and works fine. It's hard to remember what the lights mean. It would be helpful to include a small heavy paper or plastic card that could be carried with the tester that identifies the lights.


Nice quality device that helps solve problems and gives peace of mind.


I had been looking for a tester like this locally but could not find one. I ordered it and it arrived in short order, it works great and is a great addition to my tool bag!

Blue M.


Wonderful! Perfect to keep in my door pocket, just to be sure!!


This tester makes quick work out of making sure that a trailer plug is wired correctly, I typically use it to make sure that when someone uses one of my trailers that their plug is wired correctly.


Worked well. After testing, my new RV is headed back to the dealer to fix a wiring problem with the trailer light jack.


This tool reduces effort in hooking up the towed vehicle/trailer to check out trailer wiring. Simple, effective.


I love this tester. It showed me right away which circuit on my truck was out. I wish I had kept track of how many people I have helped with this tester. It is a must buy to keep in your tow vehicle.


I use it after installing trailer wiring on my trucks. Works great!



It still works fine. No complaints.


Good and useful product. Only problem is that if the Pollak keyway on your vehicle is on the bottom side you can't easily see the LED lights! This would be a more useful product if the lights were visible from both sides. Suggest a design change to do that would be appropriate.


Lights r downs on an f250 plugged in to truck


Just what I needed.... I have 4 trucks and 6 trailers, and when a light isn't working, I have to figure out where the issue is originating.... with the 7-way circuit tester, I now know the trucks are good to go..... thanks etrailer!


It works great. I have used it on several vehicles.
Only problem is using it on GM vehicles the light display is on the bottom side when you plug it in which makes it hard to read.


This is so easy to use. I keep it in the package for the easy to read light definition on the back. I love that the product is shaped like a handle for easy unplugging.


Product worked as expected. Competitively priced. Prompt shipping.


Easy to use, well made circuit tester. Great choice for a tool to throw in the truck to have ready anytime you hook up a trailer.

Show More Reviews

See what our Experts say about this Pollak Electrical Tools

  • Does Flicker of Brake Output Circuit on Trailer Wiring Mean There's an Issue
    The flicker you are seeing on the brake output circuit of your vehicle is normal. Brake controllers will lightly pulse their output circuit to check to see if a trailer is connected due to the amperage draw of the brake magnets. So what this all tells me is that your issue is most likely on the trailer side of the equation. This can be as simple as corrosion on the pins of the trailer wiring connector or it could be damaged wire, bad brake magnets or the grounds of the assemblies having...
    view full answer...
  • Will Brake Controller Show Connected with Pollak 7-Way to RV Socket LED Circuit Tester
    In regards to the Pollak 7-Way to RV Socket LED Circuit Tester part # PK12741, the brake controller may or may not read connected. This will vary from controller to controller but you should still be able to apply the override and see the light illuminate on the tester.
    view full answer...
  • Does Pollak 7-Way to RV Socket LED Circuit Tester Work With 2016 Ram Factory Brake Controller?
    There are no compatibility isseus with use of the Pollak 7-Way to RV Socket LED Circuit Tester # PK12741 so it will work just fine on your 2016 Ram 2500. I've included links to a pair of video reviews of this tester for you to check out as well.
    view full answer...
  • How Could Pollak 7-Way Tester part # PK12741 Test Brake Controller Circuit
    To use the Pollak 7-Way tester part # PK12741 that you have to test the brake controller of your vehicle will require a buddy to press the brake pedal of your truck to see if the voltage from the brake controller makes it to the tester and lights up the correct LED. Also have them use the override handle of it to see if that lights it up as well.
    view full answer...
  • Should Running Light Circuit on 7-Way Be Active When Vehicle is Plugged In
    It sounds like you're having some issues with your trailer wiring harness. In regards to a seven way trailer wring harness, the battery charge line circuit should be powered either at all time or whenever the vehicle is running. This is the only circuit that should have power under these circumstances. The trailer running light circuit will only have power when the running lights in the vehicle are turned out. This can be verified using a tester like the Pollak 7-Way to RV Socket LED Circuit...
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  • Tip for Pulling Out Fuses of 2002 Ford F-350
    Sometimes fuses can be difficult to pull out as they are pretty small, fit tightly in the slot they are installed in, and typically there's just not enough room to fit your fingers between them enough to pull them out. I'd grab a set of needle nose pliers to pull out and install the fuses of your 2002 Ford F-350.
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  • Will The Circuit Tester # PK12741 Put The Truck In Trailer Towing Mode?
    The Pollak 7-Way to RV Socket LED Circuit Tester # PK12741 will trick your 2022 GMC Sierra 3500 into thinking a trailer is connected as it uses the electrical connection to detect a trailer.
    view full answer...
  • Troubleshooting No Trailer Reverse Light Function on 2023 Chevy Silverado 3500 7-Way Center Pin
    Have you tested the center pin of the 7-Way on your 2023 Chevy Silverado 3500 with a circuit tester like part # PK12741, or have you just been testing that circuit with your boat trailer? If you've been testing it with just your boat trailer then try testing your vehicle and the trailer apart from each other. You can use a different truck with your trailer and a different trailer with your truck to accomplish this. If you have tested your reverse pin with a circuit tester and your fuse...
    view full answer...
  • First Step In Troubleshooting No Trailer Lights When lugged Into 2021 GMC Sierra
    Try testing the pins on your connector with something like the Pollak # PK12741 circuit tester to see if your 2021 GMC Sierra is actually sending power back to your trailer connector. Since the trailer worked with the other guy's truck I'm guessing that you might have some fuses or relays to change out (see your owner's manual for the correct locations) but the first step is to see if power is actually being sent from your truck. After that it's just a process of elimination; determine...
    view full answer...
  • How to Determine the Functions of the Pins on a Vehicle Side 7-Way Trailer Connector
    The Pollak circuit tester # PK12741 will tell you which functions are working in a 7-Way trailer connector but it doesn't tell you the location of the functions within the connector. But I can tell you that. If you are looking at the face of a vehicle side 7-Way where you would connect the trailer: 1 o'clock position is 12 volt power 3 o'clock is right turn and brake lights 5 o'clock is output to trailer brakes 7 o'clock is ground 9 o'clock is left turn and brake lights 11 o'clock is...
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  • Standard 7-Way Wiring For Vehicle Side Trailer Connection
    I don't know which truck or trailer isn't wired standard, but it sounds like with multiple trailers working on your vehicle that your friend's truck and trailer are wired wrong, but to fit each other. I've attached a picture of what each of the 7 pins are set to function when set up with the standard configuration. I've also attached an article on trailer wiring to help. I suggest using a circuit tester like # PK12741 to help you determine if your truck is wired correctly and what function...
    view full answer...
    Image 1 for
  • Troubleshooting 7-Way Tester Malfunction On a 2016 BMW X5 With Factory 7-Way Connector
    You will need the Trailer Connector Adapter w/ Lamp-Out Sensor Bypass # 20142 to use with your Tester # PK12741. The 7-way systems on a lot of European vehicles are very sensitive and require this adapter when being used with a tester or trailer with LED tail lights.
    view full answer...
  • Is There a Tester for Trailer Side 7-Way
    There is a tester for a trailer side 7-way (the standard blade-style, which is what I think you were referring to by flat 7-pin tester), though not a tester that you can plug in between your vehicle 7-way and trailer side 7-way; you would need to get two separate testers, one for each. For the trailer side tester, the only option is the Tekonsha Trailer Wiring Circuit Tester # 8010. This is a comprehensive tester and all you have to do is plug your trailer's standard 7-way into it and...
    view full answer...
  • Can 7-Way Circuit Tester Be Used on Upside Down Ford 7-Way
    We have 7-way testers that will work for you like the part # PK12741 but since your 7-way is upside down the display would be harder to view since you'd have to be underneath the tester. We don't have an easy solution for that unless you wanted to try and rotate the 7-way 180 degrees.
    view full answer...
    Image 1 for
  • Will the Pollak Circuit Tester Work on Newer Trucks Using LED Lights
    While the Pollak 7-Way to RV Socket LED Circuit Tester # PK12741 is designed to work with all 7-way connectors. There have been issues with vehicles such as Audi, Mercedes-Benz, and Volkswagen that have issues due to the LED lights having such a low power draw. The newer truck models are starting to have some of those same issues since they are starting to use led lights as well, so the tester will most likely not draw enough power to work. The best way to remedy that if it happens for...
    view full answer...
  • Troubleshooting Black Screen on Hopkins Smart Hitch Camera in 2013 Ford F-150 with OEM 7-Way
    I reached out to my contact at Hopkins and they suggested testing the center pin on your 7-way with the help from a friend who can shift the vehicle into reverse while you test. You can use a tester like the Pollak LED Tester # PK12741 which is super easy and simple to use. If no power is going to the center pin then check your fuse box as it may be missing a fuse and/or relay to activate the trailer tow backup lamp circuit. This is very common on Ford trucks like your 2013 F-150.
    view full answer...
    Image 1 for
  • Troubleshooting Interior Lights on Exiess Exhibitor Trailer Not Working When Connected 2021 Ram 2500
    The interior lights on your Exiess Exhibitor trailer are going to be powered of either your charge line or an onboard battery on the trailer. You can use a Test Light # PTW2993 or 7-Way Tester # PK12741 to ensure you have power coming from your 7-way to the trailer. Otherwise you will need to check your fuses to see if the charge line circuit on your 2021 Ram 2500 is damaged or missing. If the charge line is working the lights inside the trailer were likely wired to a separate battery...
    view full answer...
  • Troubleshooting Only Running Lights Working on Trailer
    The first thing to do is take a look at your owner's manual to locate any trailer fuses or relays and ensure they are all there and in working order. If they are, in order to determine the specific problem you will need to purchase a circuit tester if you do not have one - the very handy Cordless Circuit Tester # PTW2979 would be my strong recommendation due to how easy it is to use - and test the connector on your vehicle after disconnecting it from your trailer. Check the wiring going...
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  • Is There a Way To Trick 2017 Range Rover Sport Into Thinking a Trailer Is Connected For Rear Sensors
    You may be able to use a simple Tester # PK12741 to trick your electrical into thinking a trailer is connected. I tried looking for any information I could find online to verify if this would definitely work since I know Land Rover has one of the more delicate electrical systems but, I could not find any verification this would work. If you have a test light available you may be able to use that to test the theory as typically they look for a draw on the charge line or the vehicle lighting...
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  • Troubleshooting 7 Way Connector On Sprinter Class C RV
    When using a 7 pole test such as 7 Way Trailer Connector Vehicle Tester # PK12741, you plug it into the vehicle's 7 way and test each function on the vehicle and the corresponding LED's should illuminate. The RT, TM, and LT you are seeing are right turn signal, tail lights, and left turn signal. The remaining abbreviations are BU for backup lights, BK for brake controller, and 12v for 12V power output. I would start by first checking the owner's manual or contacting a dealer to determine...
    view full answer...
    Image 1 for
  • Troubleshooting Interior and Exterior Horse Trailer Lights When Hooked Up to 2020 Ram 1500
    For your situation either your 2020 Ram 1500 isn't sending power through the 7-Way connector, or your horse trailer wiring isn't working correctly for that 12V power. The easiest way to tell which end is the issue is to test the 12V power pin on your truck to see if there is power there (see attached). If you aren't seeing power then you likely need to check your fuse for that function, but if you are seeing power then that means there is a fuse or some wiring that needs to be checked...
    view full answer...
    Image 1 for
  • Interior Lights On A Hawk Trailer Pulled By A 2021 GMC Sierra 2500 Not Working
    The number 63 fuse is the correct fuse to check on your 2021 GMC Sierra 2500, and it should be your trailer battery circuit. Since you said you checked out the #63 fuse, and it's all good, I recommend checking your 7-way connector/receptacle. You'll want to ensure that your connectors are free from debris and not corroded. You'll then want to use a circuit tester like the Hook Probe Circuit Tester # PTW2993 to test for continuity at the 1 o'clock position on your vehicle side 7-way connector. Or Even...
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  • Connection Indicators on Hopkins # HM48503 7-Way Connector
    Yes, if you have correctly attached the wires to your Hopkins # HM48503 7-way trailer connector with test lights, then each of the LED indicators will light as the function is used. If the tester light does not light up, then the corresponding light or function on the trailer will not work either. I have attached a video that demonstrates how the wires are connected inside the unit, and shows how the lights come one with each feature. If you would prefer a stand-alone tester you might...
    view full answer...
  • 2004 Ford F-250 Auxiliary Charge Line Fuse for 7 Way Connector
    I'll start by saying that how your trailer lights are powered depends on how the trailer is wired; in most cases the lights on your trailer are going to be powered the auxiliary battery on your trailer and not on a separate circuit. This battery is going to be charged by the 7 way connection between your truck and trailer. I would start by verifying that your 7 way connector is providing power to all of the circuits; you can use a 7 way tester like the # PK12741 to test to make sure that...
    view full answer...
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