The heater fan switch on a Chevrolet vehicle is the electrical switch mounted in the dash that controls the speed at which the blower motor spins. Over time the contacts inside the heater switch can wear out to the point where the blower motor will no longer work. The exact procedures for replacing the heater fan switch will vary by the year and model of your Chevy. Consult the appropriate service manual for your vehicle for specific details.
Disconnect the ground cable from the negative battery terminal by loosening the retaining bolt and pulling the clamp off the negative terminal. Secure the ground cable so it cannot accidentally contact the terminal.
Remove the heater control trim panel, by carefully prying it out with a flat-head screwdriver. Be careful not to damage it. It will be the trim panel around the heater controls.
Pull out the screws that secure the heater control assembly to the dash, and carefully pull the assembly forward.
Remove the blower switch control knob.
Detach the electrical connector from the back of the switch, using your hand to depress the retaining tab and pulling the connector off the switch.
Pull out the screws that connect the heater fan switch to the heater control assembly.
Remove the heater fan switch from the heater control assembly.
Install the new heater fan switch into the heater control assembly, by sliding it into position. Then reinstall the screws.
Connect the electrical connector to the back of the heater fan switch.
Press the control knob onto the heater fan switch by hand.
Carefully slide the heater control assembly back into the dash. Reinstall the screws that secure it.
Lift the heater control trim panel into position and carefully press it into the dash.
