The heater fan is behind the glovebox. If you remove the glovebox and look up from underneath, you'll see the blower motor. It is held on by three screws. In front of it the blower motor resistor, which also sometimes goes bad.
To replace the blower resistor on a 2003 Olds Alero, first, disconnect the negative battery terminal to ensure safety. Locate the blower resistor, which is typically found under the dashboard on the passenger side, near the blower motor. Remove the screws or clips securing the resistor, disconnect the wiring harness, and then install the new resistor by reversing the process. Finally, reconnect the battery and test the blower to ensure it operates correctly.
if your blower motor is not properly working it is most likely your blower motor resistor. it is located next to the blower motor which can be found by looking through your glove compartment. 17.99 at your local autozone
check the blower motor resistor
Defective Blower Motor Resistor Pack.
the heater blower is located under the dash on the passenger side. easy to change ,4 skrews.
it is underneith the passanger dash above the black panel under the dash behind the blower motor
Most of them are visible if you drop the glove box door.
IF YOUR TALKING ABOUT YOUR A/C OR HEAT, YOU HAVE A DEFECTIVE BLOWER MOTOR RESISTOR
Blown blower motor fuse? Bad resistor pack at blower motor? Bad fan switch?
Blown blower motor fuse? Bad blower motor or resistor? Check to see if you are getting power to motor - if so motor is bad if not check fuse and/or resistor Bad switch?
heater blowe motor relay is under the hood,behind the battery there is a box that has a round knob u unscrew and on the back side it tells wich ones are wich. there are also fuses for the blower motor.that is the problem i am having. everytime turn heater fan inside car on it blows afuse.not sure why.has new resistor.