Brake lights not working

[James williams]

Ok so i have a 98 k1500. Hooked up a 4 prong trailer and drove down the road. About 15 minutes in i realized that my right turn signal was very dim. The actual signal was dim and so was the green arrow. Then suddenly both truck and trailer did not have turn signals, brake lights, or hazards. The little arrows on my dash wouldnt even show up. I Unplugged trailer and figured the trailer had grounded out somewhere (i believe it was the right side turn signal) and fixed that. I replaced 3 fuses that had popped and my hazards and turn signals came back. But my brake lights did not work. I checked my brake light relay and I also took apart my lamps and my bulbs were fine. What is really odd is that the brake lights do work every once in awhile. They only work about 10% of the time and sometimes both work other times only 1 works. (When only 1 works it is the left side) I still hear the brake light switch click but i have not tore that apart or the steering wheel harness. Im hoping im missing something really stupid and easy and i hope you guys have some ideas.

 

[df2x4]

I'm betting on corrosion or other damage to the 4-prong trailer wiring harness. It's almost always the cause of these issues. Check your ground at the junction point of the harness as well, wherever it's run to.

 

[James williams]

Well trailer is fine, no corrosion or grounding issues on the trailer itself. It has been off the truck for a few days now. The brake lights on my truck are the ones that aren't working or only working part time


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[df2x4]

That's what I'm talking about, the wiring on the truck. Where your four blade connector is by the hitch. Normally the harness is just hooked together there, but you had to unplug it and install a T there for the trailer wiring. Or at least someone did, it wasn't there from the factory. When that junction point starts going it will absolutely do the things you're describing.