Does the Computer have to be Reprogrammed on a 2005 Volvo XC90 to Install Trailer Wiring

Published 11/14/2011

Question:

I was comparing part # 118411, wire harness for the Volvo XC90 and hte dealerships model requires the copmuter for hte lights to be reprogrammed to work with the factory backup fog light. Does this unit need the same? If not, how is it different and will it pose an electrical problem for my vehicle?

asked by: Craig

Expert Reply:

The Tow Ready Custom Vehicle Wiring, # 118411 does not require that the vehicle computer be reprogrammed in order to use it. This is a powered harness that gets power for the trailer lights from the vehicle battery via a power supply at the back of the vehicle (see instructions linked). The connections to the tail lights provide the signals for the trailer.

The harness also has a fuse included and it is this fuse that protects the vehicle electrical system from any shorts on the trailer wiring. Basically, the fuse will blow and not allow current to pass through to the vehicle if there is a short on the trailer.

This harness provides the basic functions left/right turn and brake lights, and running lights. It does not have a reverse light or fog light function. I have also incldued a link to a video showign a typical installation of the harness for you.

expert reply by: Michael H