Troubleshooting LED Trailer Blinkers Towed by 2011 Mercedes GL450

Published 07/31/2015

Products Featured in This Question

7-Way to 4-Way/5-Way Trailer Adapter for Vehicles with Lamp-Out Sensors Towing Trailers with LEDs

(185)

$23.65

Hook Probe Circuit Tester

(72)

$13.14

Question:

Ive see a lot of discussion about LED lights on Mercedes and people complaining that they just flash. Well my issue is a little different. I have a 20111 GL450 w/ 7way plug. When I connect to a 4-way adapter ONLY the parking lights work on the trailer. Brake lights do not light up and flashers do not work. Is my issue still related to the low draw from LED lights on a trailer?

asked by: Bryan B

Expert Reply:

Since the running light circuit is the only taillight circuit not connected to a circuit that flashes it would lead me to believe that the problem is related to the lamp out issue that plagues European vehicles that are towing trailers with LED taillights.

Using the part # C35FR should fix the problem you are having. You can test the stop/turn signal circuits of your 7-way with a circuit tester like part # PTW2993 to verify that there isn't an issue on your vehicle's wiring first. If they don't work with the circuit tester the problem would be most likely related to a blown trailer circuit fuse or relay.

expert reply by: Jameson C