Disconnect the wire terminal from the negative terminal of the battery.
Remove the glove box (see Removal the glove compartment).
For ease of work, you can remove the instrument panel crossbar (see Removal the heater fan).
Disconnect the wiring harness connector from the regulator (see Removal the heater fan).
Using a Phillips screwdriver, unscrew the two screws that secure the regulator (for clarity, shown on a removed heater).
We remove the regulator from the heater body.
We install the electronic speed controller of the heater fan electric motor in the reverse order.
The article was reprinted from the website chevyman