The HVAC blower motor may stop working at one or more speeds due to a faulty blower motor resistor block. Our technicians recommend to confirm the resistor is at fault by first checking the operation of the switch.Google+
Car Problem Reports
Chevrolet Blazer AC Blower Inop Due to Failed Resistor
Chevrolet Blazer Problem
Average Mileage: 84,500 mi (53,000 mi - 145,000 mi)
Visitor, 2002 Chevrolet Blazer, 53,000 mi
Blower does not work at all speed settings.
Visitor, 1995 Chevrolet Blazer, 98,500 mi
heater air switch only works in 3 low speeds I pulled fuses out several were rusty.cleaned them off and clicked on and off so i checked the relay it seems to be going out after tapping on it high speed turns on for the first time in years....I am going to replace the relay Now it is the one closest to the air unit on the firewall..good luck.
Visitor, 2005 Chevrolet Blazer, 116,000 mi
The dash vent blower does not work for the two hihest speeds. I think it is the switch assembly, but don't know.
Blower Motor only functions on hi...dealer diagnosed and repaired problem
Visitor, 2003 Chevrolet Blazer, 61,000 mi
Blower only worked in the high positiom