How to Determine if a Curt Wiring Harness # C56333 is Damaged

Question:

All of the other lights seem to work on my 2010 Jeep Patriot except the Left Turn Signal on the trailer. Removed the controller after probing the YELLOW Left Turn Wire exiting the controller since it has no voltage and now Id like to know the easiest way to bench test it before I buy a new one?

asked by: Pete R

Expert Reply:

The best way to determine if the converter box is bad on something like a Curt Custom Fit Wiring # C56333 would be to check for voltage going into the box on the left turn signal to make sure that voltage is going into the box and then to check it on the outside of the box to see if the voltage makes it through the box.

If there is voltage on the in (vehicle) side of the box but none on the out (trailer) side of the box then you know that the problem is inside the box and it should be replaced. Typically, problems like this are caused by shorts on the trailer wiring that end up damaging the converter box. So I would recommend you check your trailer wiring for cut or exposed wire or corrosion and fix as necessary before you replace your # C56333.

It could also be as simple as having an insufficient ground for the converter box.

Check out the video I attached on testing a modulite converter box also.

expert reply by: Jameson C