No heat, no switch sound to control for temp is activating anything. on 1998 GMC Jimmy

Air flows to all areas when control knobs are turned. No change in air temp, heat is going to the core.

by in Elizabeth, CO on December 04, 2011
1 answer
ANSWER by , December 04, 2011
You most likely have a bad blend door actuator. You need to do proper diagnosing by a qualified tech.