How to Reset the Computer in a 2005 GMCby Katebo
If a warning or service light illuminates on the instrument panel in your '05 GMC, have the vehicle looked at and serviced by a qualified mechanic. After the vehicle has been repaired, you or your mechanic must reset the computer so that the light(s) on the instrument panel will shut off. It's important to reset the computer so that it can continue to accurately diagnose problems with the vehicle.
Locate the fuse panel cover on the underside of the driver's side dashboard. Pull down on it with your fingers to open it.
Look at the diagram on the fuse panel cover and locate the Electronic Control Unit (ECU) fuse. Take the fuse puller out of the panel and pull out this fuse.
Put the key into the ignition and turn it to the "On" position but don't start the engine.
Wait for 5 minutes then replace the ECU fuse. The warning lights will flash on the instrument panel then shut off. This indicates that the computer has been reset.