Why Does Curt Harness C55532 Need a 12V Power Wire Run to the Battery

Question:

The installation instructions for the above noted harness calls for a wire to be connected to the battery positive post to protect the vehicles sensitive electronics and wiring. What is so sensitive about the PT Cruiser wiring as opposed to other vehicles which a simple connector hookup to either the left or right rear light assembly? Thank You.

asked by: Robert

Expert Reply:

This is a common occurrence on many vehicles. Vehicle tail lights have changed over the years and they use less current than they used to. Trailer lights have not progressed as quickly. What could happen with an older traditional harness that does not have the added power source is that the trailer, with the older, less efficient lights and depending on the number of lights, could over draw the tail light circuits on the vehicle causing fuses to blow. Additionally if the trailer were to ever short circuit, it would also blow fuses or damage vehicle circuits.

Since this harness has an isolated power source, it does not pull power through the vehicle tail light system. And if the trailer would short it would blow the harness fuse instead of harming your vehicle circuits.

In short, it protects your vehicle from shorts or over drawn circuits and allows you to use new trailers with low current LED lights as well as old trailers with lots of old incandescent light fixtures that need a lot of current.

expert reply by: Patrick B