trailer wiring harness problems

[rob01]

I have an '04 liberty with trailer wiring issues. I have purchased and installed two aftermarket wiring harnesses from etrailer and both controllers burned out. I then took the jeep to U-Haul and they have installed three harnesses and again, the black box converter has blown out every time.
The most recent install lasted two weeks with the trailer never attached.
I called Jeep and they are stumped.
Anyone know where I should begin looking for the problem or know of similar issus?
Pretty frustrated, ready to sell me jeep because I bought it to haul around light boat trailer and light utility trailer. thanks

 

[LibertyTC]

Was the wring installed correctly? Something does not sound right.
Sometime's it is not the Jeep but the trailer wiring itself.
Check the wiring on trailer's including lights, bulbs& sockets, and type of wiring used on trailer's, free from cuts etc. All my wiring is heat shrink sealed and waterproof lights.
I had a similar problem and corrosion on a bulb socket was causing the problem.

 

[OneOneNiner]

If you have a schematic for the pins, check them with a tester for proper voltage(w/h brakes/turn sigs/rev), also for possible shorts to ground.
There could be a frey in the wire somewhere that is slightly resistive.

 

[Ry' N Jen]

99% of electrical problems are always bad grounding!

 

[TwoBobsKJ]

As others have stated check the grounding first. Usually the culprit and remember that trailer wiring is a complete system - the trailer harness may be bad/poorly grounded.

Since you're using a 4-pin connector to your trailer your best bet may be the Mopar wiring harness. Simple plug-n-play like the aftermarket connectors you've installed and connects directly inline with your Jeep's wiring.

Yea, it's more expensive but you won't have the issues you're dealing with now with the aftermarket harnesses. There are a number of places online you can get the factory 4-pin harness - this is just one of them. The 4-pin is in the 2nd section below the hitches.

I installed the factory 7-pin round connector and the supplemental harness and it was truly plug-n-play. With an adapter I connect to trailers with either the 4-pin flat or directly into the 7-pin when needed.

Let us know what you end up doing!

Bob