Why Does Trailer Wiring for a 2016 Mazda CX5 Have to Run to Vehicle Battery

Published 07/14/2016

Question:

To make this a true plug and play harness, I considered just running the ground and power wires to a 12V plug and plugging it in to the rear 12V outlet. As far as I can tell, it is on its own 15A fuse and separate from front outlets and fuse could easily be change to a 10A fuse if needed. Do you see any problems with this alternative method and and does this lit require fuse lower than existing 15A fuse on vehicle? Thanks.

asked by: Jose B

Expert Reply:

The reason the Curt Custom Fit Vehicle Wiring # C56310 has a power wire is to protect the delicate tail light wiring circuits of your vehicle from being overloaded. The Curt Trailer Harness # C56310 that you referenced uses your tail light circuits as signal wires and then draws the power to illuminate the tail lights of your trailer directly from your vehicle battery through the battery wire of the box. Not doing this will void the warranty of the kit.

I attached installation instructions and an FAQ on routing power wire for you to check out also.

expert reply by: Jameson C