Finding the Running Light Wire to Install Trailer Wiring Harness on a 2004 Volvo XC70

Updated 05/20/2013 | Published 05/18/2013

Question:

2004 Volvo XC70 AWD. I have located the left turn signal, right turn signal, and the brake signal on the wiring harness. I cannot seem to find which wire is for the running lights. On a Volvo, the running lights stay on all the time so its making it hard to find which one it is.

asked by: Barry

Expert Reply:

If the running lights are on all the time, even the rear tail lights, then it should be easy to find the one wire that is hot all the time. So what you would do is basically find the wire you think it might be when the vehicle is on. Then turn the vehicle off and remove the key. If the tester also goes off when the car goes off but comes back on when the car comes on then that must be the running light circuit.

You can use the video I have linked as a guide. It is on a 2011 Volvo XC70 so the wire colors might be different but the process will be the same.

expert reply by: Michael H