Videos are provided as a guide only. Refer to manufacturer
installation instructions and specs for complete information.
Allows motorhome or R.V. to power the lights on the towed vehicle without power feedback.
Please note - 3 wire system on towed vehicle: If the towing vehicle has a 3 wire system, where the brake signal is sent along a separate wire from the turn signals, then a wiring converter (118158) and 2 additional diodes are needed to retain separate amber turn signals. If you only use this diode kit (38955), then the vehicle brake lights will function as brake and turn lights.
Video of Tail Light Isolating Diode System with Wiring Harness
Videos are provided as a guide only. Refer to manufacturer
installation instructions and specs for complete information.
This part is for a vehicle to vehicle towing kit. What this basically does is, say you have an RV or motor home or pickup truck and youre going to towing another vehicle on all four wheels youre going to need this wiring harness to make the lights on the towed vehicle work with the towing vehicle. Well start by showing you the different components of this kit, its really pretty simple if you break it down. First the connection here is a traditional four pole flat. So you have your four basic signals, your ground, running lights, left turn and right turn. You also have plenty of harness to attach this on the towed vehicle. When you make your connections on the towed vehicle itself, you have to install these diodes here. At the point where you make your connections on your vehicle whether it be your left or right turn or the running light circuit you will have to install these diodes.
To give you a couple of quick notes about these, what happens is they do go in a specific direction in the wiring harness. to keep it simple basically the single prong here is listed as out, that goes onto the taillight itself out to the bulb. Then you get the two inputs here, one of the inputs is going to be the wire you just cut because youre going to splice this in between the two. It does not matter which one, the wire is going to come in one side and out the other. This other pin here is going to provide input from your trailer harness coming from the towing vehicle itself. So for instance you would take your green wire here and run it to the other open end and it will go out and power your taillight being towed down the road by the RV. As you can see theres 4 diodes and theres a reason for that. Theres going to be one for the left and right turns, and both turn signals are going to have there accompanying running lights. So youre going to need a diode for each of the running lights. Now weve opened up a small bag of parts which contains all the spade connectors needed to do the install. Basically what these are, you cut your wire that you need and you splice the wire back and expose about a quarter inch or so of it and these get crimped on. Be sure you have the right tool to do that with because it makes all the difference in the world with a tight connection and loose connection. Once you do that, it just slides onto the diode prong itself. You may also want to invest in some dielectric grease that will protect it and keep things out that would cause corrosion which would eventually cause an open circuit. As one final note you may want to take into account, if your towed vehicle has the same turn signal and brake light bulb, this kit is for you. If you have separate stop lights and turn signals, say for example your turn signals are amber that means theres going to be a different box to achieve that so you have your separate turn signals and stop lights still the same. That covers part # 38955.
Customers compare 38955 to these similar products
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Average Customer Rating: 
4.6 out of 5 stars (51 Customer Reviews)
by: Dustin W12/17/2010
Is this review helpful?
diode kit Exactly what I needed at a great price. Product is as advertised and good quality. 4282
by: js01/29/2011
Is this review helpful?
worked great 6361
by: Dave S01/25/2011
Is this review helpful?
Quality trailer pruducts at a good price, and fast delivery too.6090
by: Gordo01/20/2011
Is this review helpful?
Diodes Installed with minimal issues. I only needed 2 Diodes for my Jeep, but I'll hold on to the extras.. Seems to be a good product!5741
by: Douglas03/19/2013
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very fast shiping and exactly what was described.71552
by: Donald03/18/2013
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Just finished installing. Haven't had a chance to towe with it yet but went in just like I expected.71295
by: arthur03/08/2013
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exactly what i ordered. 69708
by: Joap03/08/2013
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fast shipping and good items 69580
by: Dennis03/05/2013
Is this review helpful?
The products were exactly what I needed and were of a very good quality. The service was fast and hassle free. I would recommend this business to anyone. 68899
by: Eldon02/28/2013
Is this review helpful?
The product is now installed and works great. The instructions were sketchy (they were literally a sketch!) but I was able to muddle through it. Instructions did not call for the signal light wires to actually connect to the (separate) signal lights which I have on my Geo Tracker. When I rewired it this way everything worked fine.67929
by: Terry02/24/2013
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The product arrived as promised and all components seem of good quality. I was apparently shorted, I don't think I dropped or lost it, one spade lug which required an extra trip to the hardware store. It would be nice if a couple of extra lugs were included incase one gets lost or messed up during install. Other than that, all worked fine as promised after install.67591
by: Joe02/16/2013
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Well pleased with service and wiring harness I ordered from your company. Great price, fast delivery, very easy to install. 66560
by: Layne01/31/2013
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Excellent value for the money. By using this kit and doing it myself I saved over $200.64665
by: Bill Springer11/21/2012
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Got the kit installed. Using on my toad (RAM Dakota) to be pulled behind my motorhome. My first one like this and easy and good quality product. Highly recommend.59891
by: Clayton11/18/2012
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It was eazy to install and worked well. Delivered on time59637
by: chuck s10/29/2012
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Easy install. Good instructions, plenty of wire length for my application (Mazda Miata). Worked perfectly first try and we are pleased with the result.58349
by: Charles09/24/2012
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Worked great. Make sure you have a good ground.55644
by: Cliff B.09/11/2012
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Exactly what I was wanting, quick delivery. I will be a return customer54367
by: Ruben V.07/23/2012
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Instructions hard to read, otherwise it worked as expected.49102
by: Don Clarke06/27/2012
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Thank you for your service and quick shipment of the diodes and wiring.Your directions on line explain a great deal of detail.45821
by: John C06/23/2012
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The diodes and wiring harness that you sent me were just as discribe and just what I needed. Thank you very much for your promped service.45378
by: James B.06/11/2012
Is this review helpful?
Delivery was prompt and product performs as advertised. The only difficulty was with the crimp-on spade terminals which are too large for the harness wire. It was necessary to solder the cable ends to make them slightly larger to get a tight crimped connection.43688
by: Bubba04/25/2012
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Works good 38336
by: chris04/23/2012
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Excellent product - better than the product was the professional support and help. These people take support seriously. would recommend to anyone.38130
by: Leonard A03/21/2012
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Excellent service from E Trailer ordered on Sunday received on Wednesday. 34649
by: Michael02/07/2012
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The kit is complete with easy to follow instructions. I have purchased from etrailer before and will do so again.31298
by: Earl Cook01/24/2012
Is this review helpful?
The product arrived in three days in very good condition. Installation went well, the video is a great help. I suggest that a longer ground wire be installed. I was required to add some length to it to make compatible with roadmaster tow bar to my motorhome. All in all a good product. Earl Cook30239
by: Glen01/16/2012
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Good product. Fast shipping. Components were sent as described. A quick install guide shipped with the product would have been helpful. Had to go back and search online for install instructions.29790
by: Allan A.11/17/2011
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The product arrived as expected & on time, with plenty of instructions and even a measure of product installation “Difficulty Rating”. I diffidently would use this measure to determine if I need help or could do it myself. Thanks for your excellent response time and “World Class Customer Service”. A.A. 27067
by: dennis d11/14/2011
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Everything exactly as promised + good v alue26947
by: charlie potter10/06/2011
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wonderful product and I cant believe how fast you delivered the parts,charlie25200
by: John C Lane10/03/2011
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Excellent service--excellent product---very easy install--- excellent in every way!24990
by: linwood m08/28/2011
Is this review helpful?
installed your isolating diode wiring harness 38955 also the blue ox base plate bx1126 . install was very easy with video on your site.was installed on my 2007 wangler to be towed with holiday rambler motor home. 22966
by: Kathleen D.08/03/2011
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Great price. Ordered extra diodes for use on 5 wire system. KWD20980
by: mick08/02/2011
Is this review helpful?
wiring and diodes in good shape and easy to install. 2010 ford edge 20937
by: Dave Shannon08/01/2011
Is this review helpful?
Nice and simple, good directions on the website. Fast order processing and shipping, very happy. Thanks again guys.20745
by: Gene F05/30/2011
Is this review helpful?
Tow bar brakets were correct ones and in excellent condition. They were delivered on time. I have ordered from E Trailer three times; each time have been completely satisfied. 15686
by: Dave P05/13/2011
Is this review helpful?
The diode wiring kit was fairly easy to install. The instructions were good and everything was delivered very quickly.13813
by: jeff03/28/2012
Is this review helpful?
Exactly as described. Best price I could find.35402
by: Gene T.02/29/2012
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Product was exactly as advertised. Pictures were exact representative of the wiring system. Delivery was reasonably prompt. Will definitely be a returning customer. thanks32800
by: Tim02/23/2012
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The product went together very easily. It was delivered in two days.32292
by: Ralph G.02/03/2012
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I installed the wiring harness on my vehicle like the video showed it works great. 31019
by: Joe G11/22/2011
Is this review helpful?
Installed the wiring kit on my 2008 Smart car. The Diode pack was exactly what I needed and made the installation simple and very clean. The kit was 100% complete in every way with more than enough wire to do the job. Thanks for a great product and at a price that made it practical.27314
by: Doug S.07/08/2011
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The ground wire is way too short. I had to add afew feet to it. This product is used by RV'ers and the towed car is going to be at least 5 feet behind the motorhome connection point.18949
by: Will Whitley06/02/2011
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Everything we get from y'all is very go od15961
by: Rod05/11/2011
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Product worked as advertised. What was great was great was the detailed installation directions.13353
by: John B.05/10/2011
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The harness arrived in a timely manor. It was straight forward to install and worked perfectly. I'm a satisfied customer.13292
by: jim A.05/10/2011
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Install went well.Good product 13232
by: Blan Patterson05/10/2011
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The Product itself was fine, but it took almost 3 weeks to get it...13174
by: Norm J.05/05/2011
Is this review helpful?
Product was as expected. Wiring instructions in box would be a nice extra.12918
by: Pete S06/07/2011
Is this review helpful?
good product and easy to install. 16355
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