Mystery "Check Trailer" warning Beep.
I have a 27 ft SunnyBrook 'Brookside' 5th wheel and a 06 Ford 250 diesel with factory brake controller.
I get a random (annoying) "Check Trailer" warning Beep and message on the brake controller. Happens most times on left hand turn, but not always. I can,t cause the problem with any method i can think of; just does it when it feels like it. I have ran down all the usual trouble shooting avenues; wiring shorts , grounding or opens. the harness and couplings all look good. Truck dealer says 99% of these cases are trailer related, but I'm not convienced because there are logic relays involved. Had a pro run through the trailer side and found nada!
Soooo, whats your take? Am I cursed or is there a logical cause to the mystery?