How to Make a Secure 12 Volt and Ground Connection for Trailer Wiring On a 2007 GMC Sierra

Expert Reply:

I agree that it sounds as if you have a ground issue. I would start by pulling apart the connector again and making sure the ground pin is not bent. Sometimes this can cause the problem.

The next place to look is under the hood at the power distribution block. The power wire is connected to a ground stud at the front of the power distribution block, see link. Make sure the wire is tight and that the fuse for the stud is properly inserted and good.

There are many ground wires and straps on the truck and specific trailer wiring ground locations are not available. I would do an inspection and make sure any ground strap or wire found is tight and not badly corroded. You could also use a 10 gauge wire, a quick splice, item # 562, and a Ring Terminal, item # DW05705-1, to splice a ground wire into the trailer connectors ground wire and attach it to the vehicle frame to ensure a good ground..

If the 12 volt power wire is still an issue, it can be resolved by using a 40 amp circuit breaker, item # PK54540, 3 Ring terminals, item # DW05705-1 and a Butt Connector, item # 05732-2, along with an appropriate length of 10 gauge wire, item # 10-1-1. You would run the wire from the vehicles positive battery terminal to the power wire at the rear of the vehicle, going into the 7-Way connector, sever the original 12 volt wire and use the butt connector to connect the new wire to that wire.

expert reply by: Bob G