bing tracking image
  1. Tow Bar Wiring
  2. Tow Ready
  3. Tail Light Converter
  4. Splices into Vehicle Wiring
  5. Universal
Vehicle to Vehicle Tail Light Converter

Vehicle to Vehicle Tail Light Converter

Item # 118158
lowest price pledge
Retail:$42.90
Our Price: $27.80
You Save: 35%
Tow Bar Wiring
Orders above $99 qualify for Free Shipping
Shipping Weight: 0.47 lbs
Quantity: 
Tow Ready Tow Bar Wiring - 118158
zoom in icon
slider vertical icon
zoom out icon
Comment field cannot be left empty.
Name field cannot be left empty.

Thank you! Your comment has been submitted successfully. You should be able to view your question/comment here within a few days.

Error submitting comment. Please try again momentarily.

Product Images

Customer Photos

Videos

Need help with installation?
Locate installers near me
Used when a motorhome with a 2-wire system is towing another vehicle with a 3-wire system, by way of a tow bar. Lowest Prices for the best tow bar wiring from Tow Ready. Vehicle to Vehicle Tail Light Converter part number 118158 can be ordered online at etrailer.com or call 1-800-940-8924 for expert service.
  • All Info
  • Reviews (132)
  • Q & A (0)
  • Photos
  • Why etrailer?

Tow Ready Tow Bar Wiring - 118158

  • Tail Light Converter
  • Splices into Vehicle Wiring
  • Universal
  • Tow Ready

Used when a motorhome with a 2-wire system is towing another vehicle with a 3-wire system, by way of a tow bar.


Features:

  • Used when a motorhome is towing another vehicle by way of a tow bar
    • If the towing vehicle has a 2-wire system and the vehicle being towed is on a 3-wire system (the vehicle has amber turn signals, separate from the brake signals), the vehicle to vehicle tail light converter will need to be used
  • This item cannot be installed backwards (the input going to the output side) to convert a tow vehicle down
  • Will not work with vehicles that have LED tail lights
  • Limited 1-year warranty


Note: You will need to install a tail light isolating diode system (38955) and 2 additional diodes (RM-792) with this tail light converter to prevent electrical feedback when flat towing a vehicle. Vehicles with separate turn signals and brake lights will need a total of 6 diodes.



118158 Vehicle to Vehicle Taillight Converter

Replaces 31820

Installation Details 118158 Installation instructions


California residents: click here



Customer Reviews

Vehicle to Vehicle Tail Light Converter - 118158

Average Customer Rating:  4.8 out of 5 stars   (132 Customer Reviews)

Used when a motorhome with a 2-wire system is towing another vehicle with a 3-wire system, by way of a tow bar.

by:

This product works well with some thought and acknowledgement that it has limitations.

I have just bought my second one. The previous one failed after five years.

This new one etrailer recommend the use of diodes to prevent feedback to the towing vehicle.
This is not a bad idea but was not previously available.

The circuit diagram that comes with this unit was misleading to me.
Eventually I figured it out and will passon what I learned.
My trailer has separate orange indicators.
It is wired as all my trailers are with a seven way plug.

You will see each diode having three connections.
Two from the towing vehicle and one to the indicator bulbs.
I just used one of the diode input tags connected to the appropriate wire from the seven way.
The output I fed to the indicator bulbs.
I have three indicators on each side of the trailer and they can all run off of the same tab.

I am enclosing a few pictures.
The first one is the old unit which was housed in a separate box screwed to the chassis.
Then I had a second box which held all the connections.

The second picture shows the new unit contained in its own box with the five diodes used.
The box is just a plastic project box from Radio Shack.

The last picture is of the finished unit all sealed and ready to go.

Now for those limitations.
Do not expect this to work as though it were an extension of a four wire vehicle.
The indicators will work and the brake lights work BUT the indicators go off when the brake is applied.
The unit cannot run the separate indicator and the brake at the same time.


Comments
No problems so far
Peter - 10/11/2021


by:

I gave up trying to find a wire to tap for a third brake light on a 2013 GMC Sierra, so I ordered a 2 to 3 wire adapter ( #118158) as recommended by you expert Michael H. He stated that only one of the inputs was needed, but both Left and Right turn were required to make mine work at all. That aside, the product was received quickly and installation was simple using the enclosed diagrams. I have never seen anything mentioned anywhere about waterproofing undervehicle connections. I do and they last for years.


Comments
Does the 3rd brake light flash when using the hazard lights?
-- comment by: Sam - 05/06/2015
Yes, emergency flashers will flash the third light also.
-- comment by: - 05/24/2015


by:

This converter worked great for what I intended it for. I was wanting to add a third brake light to back of my fifth wheel trailer. I purchased STL179RB Glolight Thinline LED also. I tried to wire this direct. It won't work, it flashes when you turn the turn signal on. A friend of mine recommended this after doing a search on the etrailer website. Etrailer support recommendation was installing two lights. Duh! that's why I wanted a third brake light, I already have two lights that function as stop/tail/turn. The installation in these pictures is not complete. I was trying to avoid drilling holes in the back of my trailer, I still may have to. I am going to enclose the wires going up the trailer to the light in some white wire loom. The light at present is secured with only white RTV, not sure that will hold. I'm still trying to avoid drilling new holes, may have to though. I hooked up all the wires on the input side, white to ground, green to right stop/turn, yellow to left stop/turn. I hooked only the red wire to red wire of the light on the output side. I hooked the ground (white wire) of light to input side of converter. Yes, it works and no it does not blink when either blinker is turned on. The additional two wires on the output side of converter are not being used nor is the additional wire of the light. Sorry for the long review, don't usually write reviews at all. Anyway, if this will help even one person it will be worth it.




by:

I use Optronics oval LED lighting exclusively and I don't think this was made to work with them because of the rapid response of the LEDs. I use this so that on a 4 wire system I can have turn signals on the side of the trailer. When you first hit the brakes, there is a fast blip of light from the side marker/turn signals. With an incandescent bulb it would be too fast to light the bulb. This is something I can live with. I think this works great with no problems so far.




by:

First off the customer service at etrailer is by far the best that I have dealt with. If I had a question, they sent me an email response very quickly. Secondly, the shipping is extremely fast. I placed the order and it came to an APO AE address (military stationed in Germany) via USPS Priority Mail and it arrived in like 5-7 days, I was shocked when it arrived, because I was expecting at least another 3 or 4 days.

So, as far as the product. Works great and was just what was needed.
Project was to make an adapter that I could plug into my 2017 Jeep Grand Cherokee U.S. spec and use a German trailer. My friend did all of the wiring and made the adapter, so I do not take any credit for any of it. Just sharing this, to those trying to figure out if it can be done.
Moving on, the adapter is a 7 pin/blade normal American plug that goes into the back of the JGC and the other end of the adapter is the 13 pin German (European) socket. We tried it without this product and all worked except when you hit the brakes the brake lights were faded and the blinker lights were lit up as if they were the brake lights. So, had to get this product and separate the brake/blinker light on the American side and have separate brake and turn wires on the German side.
Put this product between the two in the middle of the adapter, wired it up and all works great!
I used 2 zip ties around the product and a bunch of electrical tape to hold it to the adapter, at least to give it a better look.

Now I only have to plug in the adapter whenever I use a German trailer and all works correct. When done towing, remove the adapter and everything is back to the American system. Did not have to cut/splice or do anything to the wires on the JGC or the trailer, all was done at the adapter.

Thanks again to etrailer for providing awesome customer support and shipping!
Jeff




by:

The "Vehicle To Vehicle Tail Light Converter", Item #118158 is serving my needs well. I refitted my trailer completely using all LED lights. I mounted the converter inside the "C" channel underneath my tongue mounted toolbox for a little added protection. I also soldered all connections throughout the re-wire and used heat shrink &/or liquid rubber over all connections. I feel that proper planning prevents poor performance. I ordered numerous lights from etrailer also, and all are working fine. When I chose to call them with a question about one of their products, it was answered quickly and appropriately. I am a business person, and that's customer service!


Comments
The tail light converter is still working fine. I have no regrets.
Jim R - 04/06/2021


by:

I was looking for a way to add a third tail light to a vintage trailer and this proved to be just the ticket. Easy to install and worked great right out of the box.

Plenty of communications from etrailer staff along the way. Just wish they would provide tracking info so you could plan for expected receipt date.




by:

Interested in adding a third light up higher on your trailer for additional visibility? This product will separate the turn signal and brake signal on a four pin connector so you can add a running and brake light up higher to be visible. Simulates the third light that most cars and trucks have these days in the center of the back window. Positive for the semi-trucks visibility. You do not really think they can see the normal trailer lights 12" off the ground when following close behind or coming over a hill do you?
Included a picture with just the running lights illuminated.
Thank you etrailer for having the right products in stock! Most other dealers did not know what I was talking about and one even told me it was against the law. Called state highway patrol and they encouraged the additional third light! I also added the higher side running lights when semi's are merging behind you at night.




by:

Used to add little LED marker turn lights on the corners to vintage two circuit airstream trailer. The led corner lights now are red running at night, red stopping by day and switch to yellow, when turning, day or night.




by:

Since my trailer is 100% LEDs, I would not have chosen this for the two to three wire conversion since the description specifically states "not for LEDs". But after a discussion with the tech guys, I installed it and it has worked flawlessly.




by:

Sherry talked to me and found answers of what I needed and helped me attain it. Thanks a lot Sherry.




by:

Easy install, works GREAT !!




by:

I am always able to find exactly what i need here at etrailer.com. I put a camper shell on my tow vehicle and I had to wire up the high center brake light. I called Sal to find out if there was a device to kill the blinker signal to the light, and he knew exactly what i needed. It was an easy and pleasant experience. I highly recommend Sal, he is very knowledgeable and easy to work with. Thank you for the great service!




by:

This product was used to separate the brake light signal from the turn light signal on a Ford F-350 cab/chassis with a flatbed to facilitate using amber turn signals without them illuminating when the brakes are applied (truck only, no trailer). So far they are "functioning as designed" and I'm very happy with the product.


Comments
Still working fine.
Gregory V - 10/09/2019


by:

Great service on a part I wasn't aware was available. Was going to use a 7 pin adapter to power seperate lights on a little camp trailer. This will simplify my needs.
Thanks..




by:

Perfect for connecting the tail lights from my RV to my car on the car dolly.




by:

This is the second time I have purchased tow brackets and wiring kits from etrailer. Wouldn't buy from anyone else. They know their stuff.




by:

I installed a European 13pin receiver on a 2018 Ford Explorer and stowed the wiring adapter under the vehicle. Worked flawlessly so far with caravans and bike carriers.


Comments
Still working flawlessly, even with lots of snow, ice and sludge
Christian G - 03/01/2021


by:

Works great hooked it up on my Ford truck to split up the turn signals and the brake lights on my trailer




by:

Easy painless installation!
I used
this product to install a third brake light on my TC Teardrop camper.




by:

Fairly easy to install, and worked as e xpected.


Comments
No problems, so much better than a tow dolly of past years. Used it on several trips without problems.
Ronald - 02/25/2022


by:

I have used etrailer many times and have always been satisfied. If you need parts for campers, towing, etc., this is the place to go.




by:

Shipping was fast. Installation was easy. Works as designed. Couldnt ask for a better result. Now my tow car is all wired correctly.




by:

My taillight adapter arrived quickly, undamaged, and exactly as advertised. Prior to ordering, I emailed etrailer.com techs with a question. They responded quickly and with excellent advice.

This little converter is simple to install. My trailer has a shared turn signal/brake wire. The adapter allows me to connect a lighted license plate frame that also has a third brake.


Comments
What great customer service! You guys and your products are fantastic. The items I bought are working 100
John D - 03/05/2015


by:

Still working great!
Install was easy,
their online help and install videos make installation a breeze.



25
132
Show More Reviews

See what our Experts say about this Tow Ready Tow Bar Wiring





< Previous
123. . .33



Do you have a question about this Tow Bar Wiring?




  • Why etrailer.com?

    At etrailer.com we guarantee:
  • Highest quality tow bar wiring for the best price.

    Our Lowest Price Pledge ensures you will never overpay for the parts you need.
  • Real product know-how.

    We make sure that the products we sell are what we say they are, and that they work the way they are supposed to work. Get real advice from a real person who has the knowledge and expertise needed to solve your problem.
  • Most detailed, accurate tow bar wiring information available.

    Because we take providing accurate product information seriously, we take our own detailed product photos, demo videos and installation videos, as well as verify measurements, instructions, and vehicle fit information.
  • Installations, made easy.

    We love helping people and have the most highly-trained customer service, hands-on experience, step by step videos and installation instructions.
  • Fast shipping.

    Your order is automatically routed to get out of our warehouse and to your door as quickly as possible. Receive free shipping on orders over $99.
  • Personalized service for life.

    We provide one-on-one, personalized service from the ordering process through the life of your product.
  • Trusted since 1946.

    We've been serving customers since our parts store first opened in 1946 and continue to be recognized by our customers, our vendors and third parties for exceptional service.
  • Returns Policy

    Need to return an item? No problem. Please read our Returns Policy for more information.

Info for this part was:

Employee Mike L
Expert Research:
Mike L
Employee Robert G
Expert Research:
Robert G
Employee Michael H
Expert Research:
Michael H
Employee Jeff D
Expert Research:
Jeff D
Employee Jameson C
Expert Research:
Jameson C
Employee John H
Expert Research:
John H
Employee Adam R
Expert Research:
Adam R
Employee Rachael H
Expert Research:
Rachael H
Employee Jeffrey L
Expert Research:
Jeffrey L
Employee Jacob T
Video Edited:
Jacob T
Employee Adele M
Updated by:
Adele M
Employee Laura H
Updated by:
Laura H
Employee Wilson B
Updated by:
Wilson B
Employee Alexander C
Updated by:
Alexander C
Employee Isabelle B
Updated by:
Isabelle B
Employee Cole B
Installed by:
Cole B

At etrailer.com we provide the best information available about the products we sell. We take the quality of our information seriously so that you can get the right part the first time. Let us know if anything is missing or if you have any questions.