No Brake Lights when Towing New Wheelchair Trailer With 2007 Chrysler 300 Wiring # 118404

Question:

Connected my new Wheelchair trailer all LED and found no brake lights. Disconnected trailer and tested the harness flat plug coming from the car. I have power for running lights, turn signals and 4-ways but no power for brake lights. Tested on two other trailers with same results to be sure my testing was correct. All car lights are functioning correctly.

asked by: Paul

Expert Reply:

Your 2007 Chrysler 300 has a 2-wire system that combines the brake light and turn signal function onto one circuit. This means that if the brake and turn signals on the car are working correctly, the brake signal at the trailer connector should work properly, as long as the wire harness connectors and wires are connected properly and there is no damage.

The first thing to do is confirm or eliminate the wiring harness as the problem. Disconnect the trailer and test the 4-Way connector with a circuit tester, like part # PTW2993. If you find that you have the brake light signal in the terminals that the green and yellow wire correspond to on the connector, then you know the vehicle wiring is good and the issue is on the trailer. If you do not have the brake signal at these two terminals, you will need to check all of the harness wiring and connections to be sure there are no problems.

If you determine that the issue is with the trailer, the first step is to determine that all of the ground connections are correct on the trailer. A weak ground connection is the number one problem for trailer lighting problems.

expert reply by: Robert G