Troubleshooting Blown Fuse in 2007 Silverado Once Trailer is Hitched

Question:

I have a 07 Chevy Silverado and a 04 Montana mountaineer travel trailer. I can just plug my lights in without hooking up the hitch and the right turn signal works fine. But as soon as I hitch up and check the right turn signal it blows the fuse. All other light work fine it’s just the right turn signal fuse blows. New 7 way plug both ends new lights . Please help...

asked by: Dennis B

Expert Reply:

I sounds like you have a short somewhere in your trailer wiring that is blowing the truck's right turn signal fuse. When the truck and trailer are NOT hitched together the fault in the trailer wiring cannot affect the truck but once you couple them together the short can reach the truck's circuits.

I suggest you check the trailer wiring downstream of the new 7-way plug. You want to look for any wires with cracked or worn insulation, wires that may rub on the trailer frame or even on moving parts like the suspension components. Some power is leaking to the trailer's frame and once coupled to the truck this power is blowing the fuse. If the trailer has its own battery for lights, winches, jacks, etc check the wiring from the battery to ensure it is not the cause of the short.

If all the truck lights work properly and blow no fuses when the trailer is NOT hitched then you know the issue is on the trailer side.

expert reply by: Adam R