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7 Way Trailer Connector Vehicle Tester

7 Way Trailer Connector Vehicle Tester

Item # TR20117
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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. 1-800-496-5010 to order Tow Ready electrical tools part number TR20117 or order online at Free expert support on all Tow Ready products. Great prices and Fastest Shipping for 7 Way Trailer Connector Vehicle Tester. Electrical Tools reviews from real customers.
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  • Reviews (222)
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  • Videos (2)
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  • Why etrailer?

Tow Ready Electrical Tools - TR20117

  • Testers
  • Tow Function Tester
  • Tow Ready
  • Black

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

Installation Details TR20117 Installation instructions

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 Satisfaction Score:

Customer Reviews

7 Way Trailer Connector Vehicle Tester - TR20117

Average Customer Rating:  4.8 out of 5 stars   (222 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.


I have a 2019 F150 which has a 7-pin and 4-pin receptacles arranged vertically so that when you plug this tester in the lights face down and you need a mirror to see them. HOWEVER, I was able to loosen the "cable clamp" set screw and gently rotate the end so now I can see the lights. According to Tow Ready, the internal wires are not long enough to do this so just be gentle and stop when you feel the slight resistance. Might not get a full 180 degree rotation but you get enough to see the lights easily!


I bought this to be able to do a quick test of the signals coming from the car to aid in diagnosing problems. It identified a problem with brake lights not operating due to a software problem in the car.


We build and repair Trailers. Great products from etrailer!


Works perfectly and it's great have the comfort of knowing that the tow vehicle's electrical is working properly.


It was perfect to confirm my wiring setup. One minor issue is that the indicator panel was pointed toward the ground when plugged into my truck receptacle, making it next to impossible to read. Rather than return the unit, I loosened a screw and gingerly reoriented the indicator panel for best viewing. The unit works great and fulfills my needs.


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.


The product plugs in and lights up but the only fault I found is it will not check battery and brake function as should because of the Ford computer. The plug does not pull enough amps for the computer to pick up a trailer connection made. So all that lights up is the other lights such as tail, turn and marker lights. In the description it said it would work with the Ford factory (in dash) controller

Ford trucks of recent manufacture feature what Ford refers to as a smart trailer connector. The connector wont output 12-volt accessory or brake power to the trailer connector unless the electrical load from a trailer is detected.
-- Etrailer Expert Mike L - 01/10/2019


This is a must if you are pulling trailers using multiple trucks for towing. it will save you hours of work figueing out problems.

Still works great
James R - 05/31/2020


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.


Fits perfectly into 7-pin and works great, verifying everything is working properly!


This very simple device makes it easy to verify if your vehicle wiring is doing what it is supposed to be doing with the trailer lights and electrical needs. If your vehicle isn't providing the right power, stop looking at the trailer wiring! This narrows down the search for that loose wire or fuse instantly. Verifies everything is okay instantly. It's simples, rugged, and easy to stow in the vehicle to help you or others with trailer wiring issues. Highly recommend this to others.


The tester makes it very easy to eliminate the tow vehicle as a source for any trailer light or brake problems. Worth the cost for ease of testing.


I am very happy with the 7 way tester, TR20117, and used it to determine that the add on extender the RV dealer instakked on my 4Runner they hitch was changed had a loose a connection. I was able to use the tester to easily determine that the missing running lights were due to the 7way connector extension. I disconnected the extender and was able to stretch the original line to the new hitch. All is working well.
I originally ordered a Brake line and connector for my trailer and that was a UPS fiasco of no fault of I live in the country and gave them my street address thinking UPS would deliver there. They dropped the package at the wrong post office and of course my address was not deliverable. After giving my PO box number as the delivery address UPS again dropped it at the Post office to get it to me. This appears to be a new delivery method for those of us with PO boxes. Needless to say I ordered the second part because etrailer did so well in locating the problem change with UPS delivery.


I wish that I had this product many times over the years of pulling trailers with different vehicles. It makes it so easy to verify that all light connections are properly wired and working correctly. I have several vehicles and I can check each one in a couple of minutes and verify proper wiring. The test lights are bright and can be seen even in sunlight. I would recommend this product to anyone that pulls a trailer.


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.


The 7 way trailer connector tester works great. No guessing about the wiring because you just plug it in and the lights will light up showing the connection corresponding with the light on the connector tester. Saves a lot of time.


Purcased this product in conjunction with a a 5th wheel/ gooseneck trailer wiring harness. Once the wiring harnesses was installed this tester made it easy to verify that all light functions were working properly without having to actually hook up to a trailer. 5 stars!


works fine


I don't trailer very often and this is a handy tool to verify vehicle side plug is working after prolonged periods of non-use. Most issues I find are on the trailer side, i.e., broken lights and wires.


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.


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 !


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.


The product was delivered on time and was exactly as advertised. Plug and Play into the existing wiring harness. Using the instructional videos on the website, the harness was neatly installed.


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.


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.

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