Disconnect the wire terminal from the negative terminal of the battery.
For clarity, we show the operation with the heater fan removed.
We disconnect the wiring harness connector, use a Phillips screwdriver or a 7 mm head to unscrew the two screws securing the resistor…
… and remove the resistor from the heater housing.
We install the additional heater fan resistor in the reverse order.
[The original article is on the website CHEVYMAN.RU]