Troubleshooting Running Light Fuse Blowing after Trailer Wiring Harness on a 2009 Jeep Liberty

Question:

Harness installed in a 2009 Jeep Liberty. Was working fine and then started blowing the fuse for the drivers side tail light brake light works Passenger side both fine. Bypass harness and replace fuse everything OK. Put harness back in line, fuse blows. Any ideas where to look to ferret out the cause of this?

asked by: Bill S

Expert Reply:

Trace the running light circuit, which is typically a brown wire from the connector toward the rear of the trailer. Look for pinched wires or loose connections. Make sure that all the wire insulation is in good condition, with no cracks or worn spots that would allow the copper conductor to short out.

If the fuse keeps blowing without a trailer connected the problem is that the harness is bad and needs replacing as long as its installed correctly.

I attached an FAQ on troubleshooting 4-way installs plus an FAQ on trailer wiring.

expert reply by: Jameson C