Troubleshooting a 2019 GMC Sierra 1500 Getting a Check Trailer Wire Error Message

Updated 03/14/2023 | Published 03/13/2023

Question:

When I pull the trailer, I get a check trailer wiring or sometimes a check trailer brake wiring bell and even though I unplug and re the trailer wire, it keeps dinging. What’s the problem? Thanks

asked by: Cindy D

Expert Reply:

Those particular messages are often times a result of an issue with the brake control power output wire (blue wire). Since I am not sure what brake controller you are using or if it is an OEM controller, you will want to test that wire to make sure it is getting power.

This can be done using a Hook Probe Circuit Tester # PTW2993. Use the manual override on the brake controller and use the # PTW2993 tester to verify that the wire is getting power.

Since it specifically mentions the trailer brake wiring, it is most likely an issue with that blue brake control wire. Just check for power and if there is none, try and track down where the issue is. It could be that it was spliced in incorrectly or you could have faulty wiring that needs to be replaced.

expert reply by: Scott S