View Full Version : Trailer Wiring

05-29-2015, 12:19 AM
So I've read pretty much every thread about the different kind of trailer wiring but can't find what I need. I bought a Uhaul trailer hitch used for my 2003 and it came with the seven pin plug and some wiring. After reading all the horror stories about electrical issues after installing. I was hoping someone could help with how I should wire this in. I'm unable to down size the pic to upload.

05-29-2015, 12:24 AM
Buy and install the MOPAR trailer wiring kit!
No problems!
I did it.....the install takes a while, but once installed never had any
sort of issues in 100k miles (probably 30% towing a 5,200 lb. wide high cargo trailer!
Do it any other way....you might get lucky and then again????

05-29-2015, 01:29 AM
When I checked last year, the MOPAR wiring kit was discontinued and dealers were unable to get it. I used this one and it's still working great after a year. http://amzn.com/B000CMKG6O

05-29-2015, 02:15 AM
Would those blue items at the top of the photo on your link be the notorious "Scotch Clips"....?
I would not ever think of installing a kit that uses wire destroying Scotch Clips on something as
sensitive as a T1N Sprinter.
Consider yourself VERY lucky....one bad Scotch Clip disconnect/partial failure and you could be
facing complete LHM or worse.

05-29-2015, 02:40 AM
FFR545: I had that unit in the amazon link installed on my van. It broke after 14 months. The only thing I pulled was a small (but brand new, with sound wiring) utility trailer, maybe 20 times. In the end it would light up the right rear tail light of the trailer, ALL THE TIME!

05-29-2015, 02:28 PM
You will need to wire the trailer connection with a powered converter unit (module), you can get them on etrailer. Basically you take the signal from the back lights, but the power to your trailer hook up needs to come from a fused connection running up to the battery. If you go the 7 pin route, then you also need a separate power lead and a brake controller lead. None of it is difficult, but it is a lot of wire running. In addition, you need to solder the connectors on at the back tail lights for long term reliability. I have had my 4 pin connector in place for 5 years now with no issues at all.

The main thing is that you can't tap in directly - you need to use a powered module. There are threads on here that go through the whole detail - search for trailer wiring.


Gabe Athouse
05-29-2015, 02:43 PM
Yeah me too, I've purchased fancy wiring looms that snap into plugs on factory tail lamps and they were like 50$. These are like 175$-300$!? That's not going to happen! What is the good way to get a trailer wire setup witout spending that much?

05-29-2015, 03:57 PM
The modules are $50 and come with full instructions. It will give you a 4 way. If you want a 7 way, it is more wires but again doable.


05-29-2015, 05:02 PM
My solution

Gabe Athouse
05-29-2015, 05:25 PM
The modules are $50 and come with full instructions. It will give you a 4 way. If you want a 7 way, it is more wires but again doable.


Any links on this? I'd love the plug and play type but if I have to cut and solder I'm capable of that. I just don't want to freak out the van electrical system and waste time and money doing so. I think I only need a 4 way, although it might be smart to put in a better one with a brake controller since the van can actually tow a decent load.

05-29-2015, 06:53 PM
Here are some threads on wiring.


Essentially, you can use the OEM harness, or a powered module. The module is available from many folks, etrailer.com has them for $50. OEM is kind of plug and play, but the plug is up at the front of the van and somewhat involved. The first link I provided is a DIY with the module.