Troubleshooting Trailer Wiring Short On 2003 Chevy Tahoe

Question:

I have a 2003 Tahoe that the trailer fuse blows. Checking to ground I on the connector I’m showing a ground on the left and right turn/ stop terminals and was wondering if this is correct. Was thinking that 12vdc should be on those terminals when turn signal was on. Just didn’t won’t a direct short. Any wiring diagram or check out procedure would help. Thank you

asked by: Jim D

Expert Reply:

You should definitely not have a ground on the left and right turn and stop functions. When testing your connector, use a circuit tester like # PTW2993 and connect the alligator clip to a frame bolt. Then test each pin for function. If you find you are not getting the functions, you will want to check your fuses and replace them. If you have a short behind the trailer connection, check for exposed wire through insulation and you can use the circuit tester to probe through the insulation every few feet to find the correct power then replace wire as needed with # 16-1-1 for all functions other than brake output and 12V power. I recommend # 10-1-1 for those wires.

If your vehicle side wiring checks out, then you will want to do the same with your trailer. I recommend connecting each function to a battery so you don't blow fuses in your truck and you can check each function independently. You will have a common ground that needs to be bare metal to metal on your trailer frame, but you will also have ground connections at your tail lights and brake magnets. The tail lights may ground through your mounting hardware but still need to have a bare metal to metal connection.

I've attached an article and a video to assist.

expert reply by: Jason S