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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: $26.75
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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. 1-833-496-1390 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 (115)
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  • Videos (2)
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  • Why etrailer?

Pollak Electrical Tools - PK12741

  • Testers
  • 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

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

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 Circuit Tester Review

Today we're going to show you the Pollak 7-way RV socket LED tester. Part number PK12741. This tester is designed to work with seven pole connectors, works on your RV or in this case we have a truck with a seven pole built in from the factory. It has LED indicators for all the functions. We'll go ahead and cover the markings. LT for left turn, TM for marker lights or trailer marker lights, RT for right turn, [email protected] volt for our constant supply out for our trailer, BK for brake controller output if your truck or RV has it, and BU for our back-up light. Now we have six functions here, number seven would actually be our ground.

We'll take a look a the top here, you can see has all brass contacts just like any other seven pole connector. So this is very handy to keep with your trailer. If you happen to use your trailer on different vehicles, you can verify if the truck that's pulling it is working correctly or not. Let's go ahead and try it out on our truck. It plugs in just like any other seven pole connector. Line up this key with the groove.

On the connector just push it in firmly and you can let the lid rest, but I'm going to hold it up and you can see right off the bat it's showing us that we have a constant 12 volt supply from the truck. Next we'll go ahead and go through the functions and we'll make sure everything works. Okay, first off we'll go ahead and take a look at the left turn signal. Okay, that works. Now we'll turn on the running lights or the headlights. Okay, we have a good circuit there.

Let's turn that off and now we'll try the right turn signal. Okay, good function there. Of course we have our 12 volt power supply. Now our vehicle does not have a brake controller, but it would light up the same way as the other two. We've put the vehicle in reverse.

Okay, we see we got reverse light. And also if we had the brake light we'd have the brake pedal pushed on. WE can also see how the right turn and left turn come on at the same time. All right, and with that that'll finish it for the Pollak Seven-Way RV Socket LED circuit tester, part number PK12741.

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   (115 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.


Lights r downs on an f250 plugged in to truck


never worked from day 1

You mentioned that the tester did not work for you and I have a few questions that I wanted to ask. What is the year, make, and model of your truck? Do you still have the tester? Did you try it on other trucks with seven way connectors?
-- Etrailer Expert Jenny N - 10/19/2022
the vehicle is a 2016 silverado c3500 . I do not have any other vehicles to test it on. When hooking up to my other trailer no brakes all seemed ok. The tester showed no lights whatsoever. I do not possess the tester still.
-- comment by: Douglas - 10/19/2022


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.


Good company to do business with


exactly what I ordered and fast shipping


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

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!
Gary W - 06/11/2020


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
Roy - 10/12/2020


Totally transformed our 2017 Newmar Canyon Star ride. Best investment ever.


Great product, that makes a quick check to insure the vehicle is not the problem with the trail lights/brakes. Cuts the troubleshooting in half.


Nice tool to keep on hand


Does a great job, it always tell whats working or not. I have used it on other folks traiers to help get them going aging


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.


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.


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!

Wonderful! Perfect to keep in my door pocket, just to be sure!!
Blue M - 06/16/2017


Very simple tool and works great for troubleshooting issues


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.


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.


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!


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.


Just tried it and it works perfect!


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.


Very pleased

Bruce S - 11/15/2021


2021 Denali 2500 HD
Turn indicator and
emergency flasher indicators dont function

Dont buy it if you have this vehicle, which is brand new, FYI


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


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

Show More Reviews

See what our Experts say about this Pollak Electrical Tools

  • 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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  • 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...
  • 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.
    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...
  • 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...
  • 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...
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  • 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...
  • Will 7-Way Trailer Connector Tester Work With 2011 Chevrolet 2500 HD Factory Brake Controller
    The TowReady 7 Way Trailer Connector Vehicle Tester you referenced, # TR20117, is not compatible with all factory brake controllers. I don't believe it is compatible with your 2011 Chevrolet 2500 HD. A similar design that is compatible is the Pollak 7-Way to RV Socket LED Circuit Tester, # PK12741. This will work with your vehicle's factory controller and will be bright enough for outside use. You may need to shield direct sunlight from interfering with your reading.
    view full answer...
  • Troubleshooting Trailer Tail Light Functions with 2010 Toyota FJ Cruiser
    I recommend using a circuit tester like # PTW2993 to check the wire function at your 7-way. You should have both the stop and turn combined for the left side at the 9 o'clock pin position and the stop and turn for the right side combined at the 3 o'clock position. When you have the brake on, the turn signal should still function. You can use a 7-way tester like # PK12741 to test that function as well. I've attached a video to assist. If you have the both functions for each at that location,...
    view full answer...
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  • 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...
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  • 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...
    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...
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  • 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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  • 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...
  • 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...
  • 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...
    view full answer...
  • How to Test and Troubleshoot Trailer Running Lamp Circuit on 2017 Dodge Ram Truck
    There are a couple of ways to do this, the easiest way would be to use a plug-in tester like # PK12741. Simply plug the tester in to the 7-way trailer connector on your truck and have a helper activate each taillight function while you observe the tester. A circuit tester like part # PTW2993 could also be used. Turn on the running lights on the truck, ground the tester and touch the pin in the 11:00 position with the probe of the tester. If that pin doesn't show power, you likely have...
    view full answer...
  • P3 Brake Controller Does Not Light Up Circuit Tester PK12741
    The P3 brake controller # 90195 will only send back a little bit of power when just sitting so if you use the manual override on the controller then it should light up the tester solid. Using the brake pedal to test also will not work properly because the controller will not send back power if the vehicle is not moving. There are other ways to test a brake controller. In the truck cab you will need to sever the blue wire several inches from the back of the controller. Then use a circuit...
    view full answer...
  • Troubleshooting Trailer Brake Issues on 2004 Ford F-350
    It sounds like you have a wiring connection issue with your brake controller or a bad brake controller. When you plug in a trailer, your brake controller will see a power draw on your trailer brake circuit to tell the controller there is a trailer with brakes connected. From what you wrote, it seems that your brake controller immediately sends braking power to the trailer when it senses connection. I recommend first cleaning your 7-way connections on your vehicle and trailer using sand...
    view full answer...
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  • Tricky Tow Package Wiring on 2013 Audi Q7 to Think a Trailer is Connected
    Circuit tester # PK12741 will likely not draw enough power to make the tow package on your 2013 Audi Q7 think a trailer is connected. This is due to the light power draw from the LED lights. What you need is adapter # C57003 for a 7-Way to 7-Way or # TR20141 for a 7-Way to a 4/5-Way. These adapters have load resistors that will simulate additional load on the system so that the vehicle won't throw the bulb out alert when a trailer is connected. If you are just doing some testing you...
    view full answer...
  • Troubleshooting 7 Way Wire Functions on a Camper
    It sounds like your wires are most likely all wired up correctly. If you are wanting to verify that, I recommend the Pollak 7-Way to RV Socket LED Circuit Tester # PK12741. A more likely culprit is probably damaged wiring somewhere along the circuit or possibly some corrosion built up around the running lights pin on the trailers 7-way. If you have a damaged wire you would want to splice in new wires individually for the ones damaged on your 7-way wiring or splice in a jacketed 7-way bundle...
    view full answer...
  • Troubleshooting 2002 F-250 Towing Horse Trailer with Working Exterior Lights but No Interior Lights
    It sounds like the interior lights on your trailer are powered through the 12 volt circuit on your Ford's 7-way. So, start by testing to make sure that pin is active. On a standard RV style 7-way, this is located at the 1 o'clock position. I've attached a diagram for visual reference. Using a tester like # PK12741 would be the easiest. You could also simply have a case of corrosion on/in the connectors that is preventing the +12V auxiliary power from reaching the trailer. If this is the...
    view full answer...
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  • What to Use to Test 7-Way Trailer Connector
    To test a 7-way trailer connector on the rear of your vehicle you can use the Pollak Tester # PK12741. This tester is designed to work with all 7-way connectors. Another option is to use a circuit tester like # PTW2993 and go come pin to pin testing each individually. If you're trying to test the trailer side connector it's a little different. A disconnected trailer doesn't have a power source so you will need something to provide it. The Hopkins Tow Doctor # HM50928 and Tekonsha Circuit...
    view full answer...

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