Restore Towing Confidence and Clear Annoying Dash Warnings
Real-World Repair Story: The Phantom Warning Light
A customer brought in his 2008 Sierra 2500 with a frustrating problem: the “Service Trailer Brake” light would only come on after driving through heavy rain. He’d already replaced the trailer-side plug, but the issue persisted. We put it on the lift and went straight for the TBCM, located on the driver-side frame rail. Sure enough, the factory seal had failed, and we found clear signs of water intrusion and corrosion on the pins. A faulty TBCM doesn’t just fail completely; it can cause intermittent, weather-related issues that are a nightmare to diagnose if you don’t know where to look. We installed a new, pre-programmed module, and the problem was solved for good.