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trailer lighting gone weird

ckeene

Full Member
Joined
Jul 13, 2008
Messages
245
Location
Elkmont, AL
hooked up my 7pin connector from my trailer to my 05 2500. while checking the lights I noticed the brake lights do not work. with headlights on the avalanche all the running lights on the trailer work. press brake pedal all lights on trailer go off and no brake lights the trailer. have not hooked this trailer up in several months. getting dark and started to rain so I called it a day. have not checked anything so far. any ideas where to start trouble shooting?
 
Turn signals work?

Start at the 7-pin and test for voltage on the brake/turn wires, presumably pins 5 & 6. If you have 12v when applying brakes, your problem is trailer-side.

 
turn signals work , but would cause the running lights on the trailer turn off when the brake is pressed?
 
I used my tool that plugs into the truck side 7pin connector. Everything seemed good on the truck side. Going to start looking at trailer next.
 
I always start by checking for a solid ground wire connection on the trailer.

You can not get a good ground through the hitch.
 
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