Troubleshooting Emergency Flashers Not Working When Other Lights Do on Trailer Wiring Harness

Updated 08/26/2020 | Published 08/24/2020

Products Featured in This Question

Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

(78)

$53.47

Hook Probe Circuit Tester

(70)

$14.54

Question:

The trailer lights work correctly stop, turn signal and lights. When I tried the 4-way flashers they will not work at all on the trailer. This is a simple plug in system and installation was easy thus I could not understand why the 4-way system will not function. It seems that the converter box protection system is energized when the 4-way flashers are activated. Please confirm what could cause this problem. Thanks

asked by: PAUL L

Expert Reply:

This is an extremely unusual problem, but there is something we can check to get started and see what the issue might be. You'll want to use a circuit tester like the # PTW2993 and test the yellow and green wires when the flashers are turned on; test this on the input of the # C56018 side between the vehicle and the converter box to see if there is power being supplied on those circuits.

If you've already done this, and that's what you were referring to when you tested, please let me know and I can continue to assist you. It doesn't really make sense that your blinkers would work but the flashers don't.

expert reply by: Erik B