The front ac blower doesn't work on my 2003 Trailblazer. Replaced the blower motor resistor and had to add a new cable and nothing helped. Rehooked up all the old equipment (throwing hands in the air) and the next day it started to work again. Now it's stopped once again. Suggestions?

SOURCE: HOW TO REPLACE BEARING IN MY AC CLUTCH OR RELPACE ....2002 TRAILB

belt tensioner just unscrew

SOURCE: BLOWER RESISTOR BAD FAN ONLY RUNS @ HIGH SPEED

Chevrolet 2004 TrailBlazer

Look next to the blower. You can remove the panel under the passenger side. Go through the glove box and move it down out of the way to access the electrical connector. Then remove two bolts and the electrical connector.

SOURCE: NEED TO REPLACE BLOWER RESISITOR. FAN ONLY WORKS ON HIGH SPEED

Under the dashboard on the passenger side you will see the blower motor. Near the blower motor inside the air duct is the resistor. It should be held in place by two screws. Hope this helps. Good luck

SOURCE: rear tops vents on 2005 trailblazer dual ac system

it wont be the blower motor, sometimes the switch. but you replaced the control switch already, the only thing left would be the actual actuators or a wire problem. like a stepper motor controlling a flap to let the air out those vents. SO either the stepper motor that controls your rear air flap/vent is inop, or its not recieving the power or ground coming from your control switch due to broken or damaged wire.

SOURCE: bad ac blower resistor

the resistor is only give you the speed of your blower motor ( inside fan )
it does not have any thing to do with cold or hot