Auxiliary Climate Control

AUXILIARY CLIMATE CONTROL

Auxiliary Climate Control Housing:

NOTE: An in-line filter is installed in the auxiliary evaporator inlet jumper line at the underbody peanut fitting near the floorpan line bracket. A restriction in this filter may cause misdiagnosis of a failed thermostatic expansion valve. Before a new thermostatic expansion valve is installed, this filter must be inspected and in the event of an internal compressor desiccant failure, a new filter must be installed.

The auxiliary climate control system is a 1-piece unit that is located on the LH side of the vehicle between the side windows and the floorpan, behind the rear wheel well. The driver has primary control of the auxiliary climate control system or can transfer control to a rear passenger control panel.

All of the auxiliary climate control system components are serviceable from the inside of the vehicle except the lines.

Auxiliary System Air Distribution
A vertical air distribution duct supplies air to the integral headliner air distribution duct. Airflow is then directed to the passengers through adjustable registers. The heater floor duct supplies air to a fixed register which is integral to the side trim panel and directs airflow through the fixed register to the passenger compartment.

System Airflow:

System Airflow
The auxiliary climate control system has the following features:
- The auxiliary blower motor recirculates the air inside the vehicle. Outside air is not available to the auxiliary climate control system.
- Air is cooled and dehumidified by the auxiliary evaporator core only if the dual-zone electronic air temperature control (EATC) is adjusted to a position that requires A/C compressor operation.
- The temperature blend door and the air distribution door are controlled by electronic actuator motors.
- Movement of the auxiliary temperature control between COOL and WARM causes a corresponding movement of the temperature blend door to mix air flowing through and around the auxiliary heater core.
- Toggling of the auxiliary air distribution control between PANEL and FLOOR causes a corresponding movement of the air distribution door to direct airflow between the panel (headliner) registers and the floor duct.

Blower Motor
The auxiliary climate control system contains a blower motor which is controlled by the blower motor switch on the front or rear auxiliary climate control assembly.

Control Assembly
The auxiliary climate control system has dual controls for the driver and rear passengers consisting of temperature, blower speed and air distribution mode. The front auxiliary climate control assembly is mounted in the overhead console. The rear auxiliary climate control assembly is mounted in the rear of the front floor console assembly.

Heater Core
The auxiliary climate control system uses a rear heater core which operates in the same manner as the front heater core.

Evaporator Core

NOTE: The auxiliary evaporator core is not separately serviceable. It is serviced only with the auxiliary climate control housing.

The auxiliary climate control system uses a rear evaporator core which operates in the same manner as the front evaporator core.

Thermostatic Expansion Valve

NOTE: An in-line filter is installed in the auxiliary evaporator inlet jumper line at the underbody peanut fitting near the floorpan line bracket. A restriction in this filter may cause misdiagnosis of a failed thermostatic expansion valve. Before a new thermostatic expansion valve is installed, this filter must be inspected and in the event of an internal compressor desiccant failure, a new filter must be installed.

A thermostatic expansion valve automatically regulates the flow of refrigerant into the auxiliary evaporator core. It is also the dividing point in the system between low- and high-pressure sides.

The temperature sensing bulb measures the temperature of the refrigerant in the suction line and transmits it to the thermostatic expansion valve. This temperature variation regulates the refrigerant flow to the auxiliary evaporator core.
- When the bulb senses a high temperature, the thermostatic expansion valve opens and floods refrigerant through the auxiliary evaporator core.
- When the bulb senses a low temperature, the thermostatic expansion valve starts closing to shut off the refrigerant to the auxiliary evaporator core.