How to Test Trailer Wiring for 2016 Jeep Compass to Determine if 4-Way is Functional

Updated 07/09/2018 | Published 07/05/2018

Question:

Just received the harness today. Installed it and the driver side is working great. The passenger side the yellow turn light, lights up upon applying the brake and the red brake light flashes as the turn. Never plug it in to the trailer yet.

asked by: David Y

Expert Reply:

Try plugging in a trailer to the 4-way of the # C56344 and you should find that it works fine. Testing the wiring on the input side of the box doesn't always tell you if the harness is working.

If you wanted to further test the wiring though test the pins of the 4-way. The brown wire should have only running lights, yellow should have left turn/stop, and green should have right turn/stop.

expert reply by: Jameson C