How to Route the Power Wire From a Trailer Wiring Harness to the Battery on a 2008 Nissan Maxima  

Question:

Expert Reply:

I have included a link to the CME-PCL-INS sheet and the instructions for CURT Wiring Harness, # 56022. The instructions to run the power wire to the battery are generic in that they do not offer a specific method for routing the wire to the battery. But, I can offer some tips and 3 ways you can route the wire.

Method 1: Fastest and Easiest

After you have installed the wiring harness according to the installation details you will be ready to route the power wire to the positive battery terminal. Start by attaching one end of the long wire to the converter. From there you can follow along an existing wiring harness or on the outside of the frame to the front of the vehicle, using wire ties to hold up the wire, and avoiding areas that may pinch or burn the wire. Ultimately you will route it up through the engine compartment to the battery.

The benefit of this method is it is fast and easy. The drawback is that the wire is exposed (however in everyday conditions, the wire will be fine).

Method 2: Not as Fast, Not as Easy

For this method you will start out as in method 1. Instead of following along an existing harness or outside the frame rail, you will route the wire through the frame. This would require first routing a long, skinny, rigid item, like a straightened coat hanger, from the front of the frame rail to the back, tieing off the wire to the hanger, and then pulling it through the frame from the front.

Some frames will require that you weave the wire in an out of the frame as you work your way forward. Once at the front of the vehicle you will route the wire through the engine compartment, avoiding areas that could pinch or burn the wire, and over to the battery. The benefit is the wire is more protected. The drawbacks are that it takes longer to install, and if the wire should break at any time during the life of the harness, you would have a hard time finding and fixing the break.

Method 3: Most Protection, Longest Installation

This last method involves routing the wire through the inside of the vehicle. After attaching the power wire you would find a way to route it into the trunk area and from there route it into the back of the vehicle. At this point you would need to select the best path to run the wire. You would most likely have to loosen or remove interior trim pieces to hide the wire. Running it along the driver side front and rear doors is the most direct path.

You would then need to route it through the firewall, which may involve drilling (careful not to drill through something on the other side). Then go through the firewall to the battery. The benefit here is the wire is the most protected of any method. The drawbacks are that it is time consuming, you may run out of wire depending on the path you take through the vehicle, and troubleshooting the wire would require uncovering it from where it is hidden.

expert reply by: Michael H

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