Unplug the cable of the negative battery terminal. Can strip off to greater access to the heater case and blower motor. Unscrew the wiring harness cover and remove the electrical connector of the blower motor. Disbutten the screws that mount the blower motor and very carefully ease the blower motor out of the housing along with the electronic control unit, but the weight of the motor should never come to bear on the fan. Removal of the electronic control unit from the motor requires the removal of the screw found below that of the rubber cover by prying off the cover, then flipping the cover upside down and removing the fan and the motor to reach the control unit. Unscrew the screws that are holding the control unit together, un-attach the electrical connector, and remove it. Removal is the opposite of installation, but it should run the exhaust fan and you should check that it is functioning properly.