Why Does Curt Trailer Wiring Harness # C56165 Require Wiring to the Positive Side of the Battery

Published 08/07/2014

Question:

I am installing on a 2009 toyota rav4. Why can,t i use the 12V aux. power outlet in the right rear panel instead of running the power lead to the battery? It is also a 10amp circuit. thanks,

asked by: Carl D

Expert Reply:

Some trailer wiring harness 4-Way and 7-Way connectors require a power wire to be routed from the harness to the vehicle battery. The power wire is required on trailer wiring harnesses for some vehicles because the electrical system on those vehicles cannot handle the amperage draw associated with trailer lights. The power converters and ModuLites used in these applications connect to the vehicle battery to provide the power for the trailer lights, protecting the vehicle's sensitive electrical system.

If you were to connect the power wire to the 12 volt auxiliary circuit of your 2009 Toyota Rav4 you would be defeating the circuit protection feature of this harness. I can't safely recommend you install the Curt Wiring Harness part # C56165 any other way than by connecting to the positive side of your battery.

I attached an install video for this harness as well as an FAQ on routing the power wire for you to check out.

expert reply by: Jameson C