Installing Trailer Wiring Harness for a 2010 Lexus RX 450h

Updated 10/20/2014 | Published 10/18/2014

Question:

Please clarify: I have the #118255 kit. My vehicle does not have the tow package, cooling system upgrade. There us a four pin socket for the trailer behind the rear bumper for a 4 pin trailer pig tail. I have connected the pig tail to the socket located behind the rear bumper and there is no power coming through during the tests. I have checked the fuse compartment ant there is a 30A fuse OK in the trailer light location. Question: Is there a software configuration that has to be programed to activate that circuit or will I still need to locate the junction behind the side paneling compartment per instructions. I dont to risk damaging any of the electrical components.

asked by: Steve M

Helpful Expert Reply:

If you haven't plugged in the converter box portion of wiring harness # 118255 (the part with the yellow fuse holder) then the 4-Way will not work until you do. Inserting the fuse in the fuse holder would be the last step.

This harness is circuit protected. This means that if there is a short on the trailer it will not damage the vehicle wiring or electronics.

You should not have to have the vehicle computer flashed or reprogrammed to use the harness.

expert reply by: Michael H