Replacing the blower motor is a straight foreward repair.
Under the passenger side dash unplug the blower motor connector. Remove the three screws that hold the blower motor to the housing and lower the blower motor/fan. Remove the lock ring that holds the fan to the blower motor shaft. While holding under the fan have someone take a hammer and punch and knock the shaft of the blower motor out of the fan. Install the fan onto the new blower motor shaft, install the lock ring, install the blower motor/fan back into the housing, and plug in the connector.
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