Chevrolet Trailblazer EXT blower only operates on high speed with non-functional controls on Chevrolet Trailblazer EXT

Some Chevrolet Trailblazer EXT owners report experiencing issues where the blower only operates on high speed, with other speed controls becoming non-functional. This problem is often linked to a malfunction in the blower motor resistor, which is crucial for regulating fan speeds. Additionally, owners may find that a faulty fuse, relay, or wiring within the HVAC system could also contribute to this issue. To effectively diagnose and resolve the problem, it is advisable to check the blower motor resistor, fuse, relay, and wiring.