Service Trailer Brake System light came on without towing on 2007 GMC Sierra 3500 HD

The servcie trailer brake system light just came on and i'm not towing anything.

by in Hagerstown, MD on July 23, 2010
Get Your Car Fixed at a RepairPal Certified Shop.
We certify shops based on expertise, quality work, and verified customer reviews
1 answer 1 comment
ANSWER by , September 29, 2010
turn on the off tow haul mode on end of shifter
COMMENT by , February 29, 2012
that all i have to do and the light will go off,the truck is a 2010 gmc sierra 2500 hd