My trailblazer has a manual heating/ac system with 5 fan speeds. Earlier this year speed 5 did not work (fan did not run) Now Speeds 1,2,& 3 do not work and 4 and 5 work. Is the problem in the switch or the fan motor. How hard is it to replace the switch?
The problem most likey is with the blower motor resistor pack. This series of resistors is what controls all the lower blower speeds.
This is located in the heater box next to the blower motor. Go to the dealer and purchase a replacement resistor pack, and then you’ll know what it looks like and where it’s located.
Tester