Auxiliary Climate Control

AUXILIARY CLIMATE CONTROL

An optional auxiliary A/C and heating system is available. The auxiliary climate control housing is located on the LH side of the vehicle behind the rear wheel well.

Air Distribution
Vehicles with trim have a vertical duct that supplies air to the integral headliner A/C duct. Air is supplied to the passengers through six adjustable registers. The floor duct is integral to the side trim panel and has 4 fixed registers. The trim panel connects directly to the auxiliary A/C-heater unit.

Vehicles without trim do not have overhead registers or floor ducts. A unique register is used to distribute air-conditioned air and a heater outlet duct assembly distributes heated air.

System Airflow
The function selector switch (located in the front A/C control) controls the air distribution for both the front and auxiliary systems.
- The mode door is driven by a vacuum control motor to its predetermined position.
- When the function selector switch is in the FLOOR or MIX position, the auxiliary system will direct air to the floor.
- When the function selector switch is in the VENT position, the auxiliary system will direct air to the overhead vents.
- When the function selector switch is in the NORM A/C or MAX A/C position, air-conditioned air is distributed through the overhead registers.
- The auxiliary system uses only recirculated air from the vehicle interior.

Blower Motor
The auxiliary climate control assembly contains a blower motor. It is controlled by the blower motor switch on the front climate control assembly.

Heater Core
The heater core consists of fins and tubes arranged to extract heat from the engine coolant and transfer it to air passing through the heater core.

A/C Evaporator Core
The evaporator core is the plate/fin type. A mixture of refrigerant and oil enters the bottom of the evaporator core through the evaporator core inlet tube and is routed so it flows through the partitioned plate/fin sections. Refrigerant then moves out of the evaporator core through the evaporator core outlet tube.

Thermostatic Expansion Valve
A thermostatic expansion valve (TXV) regulates the flow of refrigerant into the auxiliary evaporator core. It is also the dividing point in the auxiliary portion of the refrigerant system between the low-and high-pressure sides.

The TXV includes a temperature sensing bulb which measures the temperature of the refrigerant in the suction line and transmits it to the TXV. This temperature variation regulates the refrigerant flow to the auxiliary evaporator core.
- When the bulb senses a high temperature, the TXV opens to increase refrigerant flow through the auxiliary evaporator core.
- When the bulb senses a low temperature, the TXV starts closing to decrease refrigerant flow to the auxiliary evaporator core.