Troubleshooting Trailer Wiring Warning Message in Vehicle Display

Question:

How do you turn the “check trailer wiring” alarm off?

asked by: Will

Expert Reply:

If your vehicle dash display shows a warning for trailer wiring usually this visual indicator can be reset by disconnecting the trailer and shutting off the engine for a few minutes. You didn't mention your specific vehicle but the question you referenced concerned a 2015 Silverado 1500; I checked an online owner's manual for this vehicle and there is no mention of a 'wiring alarm' or a 'trailer alarm' that I could find in that online version of the manual.

Once the alarm is reset you can test your trailer connector for the proper signals on each of the contacts. This is easiest with a simple circuit tester like # PTW2992 or # PTW2993. Have a helper engage each function (brakes, turn signals, running lights, trailer brakes) while you apply the tester to the appropriate pin for that function. You can refer to the linked image that shows a 7-way socket and the signal that should be found on each of its contacts.

Something as simple as trapped water or dirt, or slight corrosion within the connector or in the wiring plus that leads to it could cause the vehicle systems to think there is a fault in the trailer wiring. The trailer's plug likewise could have corrosion that has caused a short between adjacent circuits and this could trigger a warning in the vehicle systems.

expert reply by: Adam R