blower problem

o3 chevy impala and the defoster blower only works on high lower speeds stopped working all of a sudden where is first place to check to fix the problem? thanks for the help

The blower resistor is usually the problem. The high speed is on a separate circuit from the lower speeds which use varying numbers of resistors to drop voltage which drops the fan speed. Its usually the resistor for the speed just under high that causes all the lower speeds to stop working since all the lower speeds require that resistor in order to work.

i am going through the same problem with my 01 impala. It is all fixed now, i replaced the resistor and i have all the speeds. It was a pain in the butt to change the resistor due to it being right up against the firewall. You can loosen and remove 2 of the 3 screws but the 3rd one is the bear.