Wiring question

Something is wrong with the wiring from my truck to trailer. When it's plugged in everything is working (brake lights, blinkers) When I'm driving though and I hit the brakes the dash lights go out, which doesnt happen when the trailer isnt hooked up. Any suggestions before I re-wire the trailer

 

Make sure you have a good ground from the trailer frame to the truck and that the lights are grounded well also.

 

depending on what make truck you are running on this one, after checking the usually suspects. Check the actually head light switch for the truck. Ford trucks are well known for melting the plug and wires or switch its self when even minimal voltage is pulled through the switch, such as a trailer lighting. Just something to check if all else fails

 

Its odd I rewired the trailer, same thing though, blinkers, brakes everything works but dash lights still go out, and arrow flasher in the truck stops when I apply brakes. Take the trailer off an no problems I guess I'll just let it go considering everything does work outside the truck kinda annoying though. Winter project I guess. Oh an its a chevy silverado to no Fords in my garage

 

:blob3: sounds like a grounding problem, check to make sure all wires are secured well and that the is no wire contact to the frame of the trailor, also make sure your ground is snug to a "cleaned" part of the trailor. by cleaned i mean absolutely no paint use a disc grinder and clear away any paint or rust. good luck tony.


also very important take you harness and open it up make sure there are no wires touching, i would start there make sure there are no stray wires touching other terminals.

 

If it's not a ground - I'm betting that the brake pedal is actually causing the problem by contacting wiring/causing bad connections or a short - may be time to crawl underthe daaash and actaully watch the pedal as you depress it with your hand.

 

check the truck side of the trailer lights
for a bare wire causing a short.
real common on 4 pin flat plugs