2003 Chevy Silverado, heater motor runs after ignition is off
In the underhood fuse box there's a relay marked "blower". Try tapping it with the handle end of a screwdriver. It's probably stuck on. This would allow the fan to run even with the ignition off. I'd suggest replacing it. HTH. -Jim
Search Chevrolet Silverado 2500HD Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Chevrolet Silverado 2500HD Experts