Auxiliary Climate Control

AUXILIARY CLIMATE CONTROL

Auxiliary Climate Control
The auxiliary climate control system is a one-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 control of the auxiliary climate control system using the auxiliary climate control assembly.

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 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:

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 instrument panel mounted climate control assembly is adjusted to a position that requires A/C compressor operation.
- The temperature blend door and the air distribution mode 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 direct blower motor airflow through and/or 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 auxiliary climate control assembly.

Control Assembly
The auxiliary climate control system control consists of temperature, blower speed and air distribution mode. The auxiliary climate control assembly is mounted in the overhead console.

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

Evaporator Core
The evaporator core is an aluminum plate/fin type and is located in the auxiliary heater core and evaporator core housing. A mixture of refrigerant and oil enters the bottom of the evaporator core through the evaporator core inlet tube and then moves out of the evaporator core through the evaporator core outlet tube. When the A/C compressor is operating, air from the blower motor is cooled and dehumidified as it flows through the evaporator core fins.

Thermostatic Expansion Valve

NOTE: An in-line filter is installed in the auxiliary evaporator inlet line at the floorpan bracket connection. A restriction in this filter may cause misdiagnosis of a failed thermostatic expansion valve (TXV). This filter must be inspected before a new TXV is installed.

The TXV restricts the flow of refrigerant from the high pressure side of the refrigerant system and separates the low pressure and high pressure sides of the auxiliary refrigerant system. Refrigerant entering the auxiliary evaporator core passes through the TXV. A temperature sensing bulb senses the temperature of the refrigerant flowing out of the evaporator core and adjusts an internal pin-type valve to meter the refrigerant flow into the evaporator core. The internal pin-type valve decreases the amount of refrigerant entering the evaporator core at lower temperatures and increases the amount of refrigerant entering the evaporator core at higher temperatures.