Three problems related to blower have been reported for the 2003 Chevrolet Trailblazer. The most recently reported issues are listed below.
The middle heat and air conditioner blower would not blow air. The defrost and floor blower did blow out air. As of November 2008 none of the blowers blow out air except for brief occasions. If the blower does work then this creates a problem because it won't shut off and the battery goes dead. I've read about several owners with this same issue. The suggested temporary fix for this issue is to look up from the gas pedal and there are two units, one controls the defrost and foot blower and one controls the middle blower which is harder to get to. It has been identified that there there is a pin for each unit that slipped out and needs to be reconnected. One customer indicated it looked like it was meant to fall out at some point, in other words for gm to make revenue for the repair costs. This is extremely frustrated and I request that this is considered as a recall and gm immediately fix this issue at no cost. Gm has given an estimated quote of $800 - $900 to fix the actuary. Thank you for your help and this service.
The blower fan for the heating & air contioning system failed, due to a defective design or poor workmanship in the outside air supply duct, allowing small animals (like mice & chipmunks) to get inside. The Chevrolet dealer replaced the blower motor, charging me $187. 87 for the repair,saying that it's not covered by the warranty. My 2003 Trailblazer should be coved by gm's warranty. This repair does not fix the problem of small animals getting to the blower motor.
After extended driving of my 2003 chevy Trailblazer lt ext, my heat (auto. Dual climate control) begins to blow cold air, and during the summer it blows hot air.