Following manufacturer's instructions, connect an approved refrigerant recovery/recycling/recharging unit to the AC system and discharge the system. Drain the engine coolant. Remove the complete IHKA housing, then take out the heater core and blower motor resistor. While working with the IHKA housing out of the vehicle, remove the temperature sensor and disconnect the electrical connection. Unclip the linkage on the stepper motor, then remove the stepper motor and disconnect it from the harness. Release the screw and unlock the plate from the IHKA housing, using locating tabs during installation. Unclip the wiring harness from the IHKA housing, turn the cam disc until the microswitch is unclipped, and then remove it. Release the screws on the blower housing and feed out the double pipe. Unclip the clamps on the IHKA housing cover and remove it, followed by the expansion valve and A/C Evaporator Core. Installation is the reverse of removal, and always replace O-rings when reconnecting refrigerant lines.