Blower Controls System Check
WARNING: This page is about a different car, the 2002 GMC Safari and 2002 Chevrolet Astro. However, it is still accessible from the selected car via links, so may be relevant.
Turn ignition switch to ON position. Move front or auxiliary blower speed selector switch from low to high positions and listen for increase in blower motor speed at each switch position. Move blower speed selector switch from high to low positions and listen for decrease in blower motor speed. If blower motor is inoperative in any or all speeds, go to appropriate diagnostic procedure for main (front) or auxiliary (rear) blower motor.