Auxiliary Climate Control Assembly

The auxiliary climate control assembly is installed on the left side of the luggage compartment, behind the rear quarter trim panel. A grille in the trim panel allows air to flow from the luggage compartment into the auxiliary climate control assembly.

The auxiliary climate control assembly consists of a casing, formed from a pair of plastic moldings, which contains:

• An evaporator
• A heater core
• Temperature blend doors
• A distribution door
• A blower
• A blower control module
• An evaporator temperature sensor.

Refrigerant and coolant pipes from the engine compartment are connected to pipes from the evaporator and the heater core in the rear left wheel arch. An evaporator drain tube, sealed with a foam rubber gasket, locates in the top of the left side member of the rear floor.

Two parallel air steams flow from the blower through the evaporator and heater core to two pairs of distribution outlets. The left and right air streams supply the related rear zones of the passenger compartment. The front pair of distribution outlets supply the vents in the seat side bolsters and the carpet. The rear pair of distribution outlets supply the vents in the headliner.

The left and right air streams each contain two temperature blend doors connected together with a link mechanism. Separate electric motors, installed on the rear of the casing, operate the temperature blend doors to give independent temperature control for each rear climate zone.

The left and right air streams share a common distribution door installed below the distribution outlets. An electric motor, installed on the top of the casing, operates the distribution door.

A Local Interconnect Network (LIN) bus connects the distribution motor and the temperature blend motors in series with the Automatic Temperature Control Module (ATCM). The motors are powered by feeds from the ATCM and share a ground connection with the auxiliary blower and auxiliary blower control module.

The ATCM determines the positions of the distribution and temperature blend doors. It uses either their closed or open position as a datum and memorizing the steps that it drives the individual motors. Each time the ATCM is activated, it checks the memorized position of the motors against fixed values for the current distribution and temperature settings on the control panel. If there is an error, the ATCM calibrates the applicable motor, to re-establish the datums. This done by driving it fully closed or open before resetting it to the nominal selected position. A calibration run can also be performed using approved diagnostic equipment.