Passing the Trailer Wiring Power Wire Through the Fire Wall on a 2008 Nissan X-Terra

Question:

Just how, being very specific, does one get the red wire through the firewall, when the rubber fitting around the existing wire harness is very solid and doesnt seem to have extra room in it? Is there a special tool to use as a probe/guide?

asked by: David D

Expert Reply:

Passing the wire through the fire wall is different for most every type and year model of vehicle. I would try to find a grommet, as you have, and remove it from the fire wall. If you can find a grommet with fewer wires running through it you will have a much easier time reinstalling it. Once the grommet is removed I would cut a small slit in the edge of the grommet with a razor knife, being careful not to cut any of the existing wiring. Pass the power wire from the trailer wiring harness through the slit in the grommet and run it to the vehicle battery through the supplied inline fuse holder.

I would not use a probe or a knife to try to force the wire through a grommet or poke a hole in it, while it is still installed, due to the possibility of penetrating other wiring or critical parts.

You can usually find a place to run the power wire that is easier than the main wiring harness. Sometimes the grommet for the emergency brake cable is accessible and easily used.

expert reply by: Robert G