Trailer wiring - HELP!!

I am a self professed electrical moron.

Does anyone have a definitive answer on 1990 trailer wiring. Simple utility trailer. No bells or whistles. Running lights, turn signals, brake lights. Running lights and signals work, no brake light. All lights on Jeep work.

All the harnesses I've found are for 91 and up. I need 1.) part number (or just a name) and a simple wiring diagram would help too. I'm just about to give up and take it in to get done. I know it can't be that complicated.

Thanks

Probably a grounding problem. Make sure it's well grounded. Trailer lights are notorious for having gremlins in them.

Just put one on mine, its a Hoppy(made by Hopkins)tailight converter.

Part number, 310-0041-560

I bought mine at Advance Auto. Note it is not plug and play, you will have to connect some wires.

I went to use my trailer harness for the first time in a number of years. Everything worked, but the right turn signal. Turned out the electronic box probably had a diode that fried. A replacement harness from a local trailer shop got me back onto the road. Now I make sure that the protective cap is on good for in-between uses as it is most likely that it hit something metallic in my hatch and shorted out. If your harness is old that could be the explanation as well.

When I built my trailer for hauling my quads and towing my XJ, I made sure to run good electrical. Here is how I did the ground, and after almost 2 years I have had 0 problems.








Hope this helps...