Auxiliary Climate Control
Auxiliary Climate Control
Auxiliary Climate Control System
The auxiliary climate control housing 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 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 heater floor duct supplies air to a fixed register, which is integral to the side trim panel.
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 main HVAC module is adjusted to a position that requires A/C compressor operation.
- The temperature blend door and the airflow mode door are controlled by electric actuator motors.
- Movement of the auxiliary temperature/mode control between COOL/ROOF and WARM/FLOOR causes a corresponding movement of the temperature blend door to mix air flowing through and around the auxiliary heater core and also causes a corresponding movement of the mode door to the ROOF and FLOOR positions.
Blower Motor
The auxiliary climate control system contains a blower motor, which is controlled by the HVAC module or rear auxiliary climate control assembly.
Auxiliary Climate Control Assembly
The auxiliary climate control system has dual controls for the driver and rear passengers consisting of temperature/air distribution and blower speed. The front auxiliary climate controls are built into the HVAC module. The rear auxiliary climate control assembly is mounted in a separate overhead console positioned on the headliner above the second row seating area.
Evaporator Core
The auxiliary climate control system uses an evaporator core, which cools and dehumidifies the airflow from the auxiliary blower motor when the A/C compressor is operating. All airflow from the blower motor passes through the evaporator core.
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.
Thermostatic Expansion Valve (TXV)
The Thermostatic Expansion Valve (TXV) is located behind the LH rear quarter trim panel at the auxiliary evaporator inlet and outlet. The TXV provides a restriction to the flow of refrigerant from the high-pressure side of the refrigerant system and separates the low-pressure and high-pressure sides of the refrigerant system. Refrigerant entering and exiting the evaporator core passes through the TXV through 2 separate flow paths. An internal 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.
Underbody Auxiliary A/C Lines
The underbody auxiliary A/C lines carry refrigerant to the auxiliary A/C evaporator inlet and away from the auxiliary A/C evaporator outlet. The auxiliary underbody lines have the following characteristics:
- The auxiliary evaporator inlet line carries high-pressure refrigerant liquid from the TXV manifold and tube assembly to the auxiliary evaporator.
- The auxiliary evaporator outlet line carries refrigerant vapor from the auxiliary evaporator to the TXV manifold and tube assembly.
Underbody Heater Lines
The underbody auxiliary heater lines have the following features:
- The underbody auxiliary heater inlet line is a aluminum tube assembly that carries coolant from the engine coolant supply line to the auxiliary heater core inlet.
- The underbody auxiliary heater outlet line carries coolant from the auxiliary heater core to the front heater core outlet line.