Auxiliary Climate Control

AUXILIARY CLIMATE CONTROL

Heater And A/C Assembly:

An optional heater and air conditioning assembly is available. The system is a one-piece unit that is located on the RH side of the vehicle between the side windows and the floorpan, behind the rear wheel well. The driver has primary control of the auxiliary air conditioning and heating system or can transfer control to a rear passenger control panel.

All of the auxiliary A/C-heater system components are serviceable from the inside of the vehicle except the lines.

Air Distribution
A vertical duct supplies air to the integral headliner air conditioning 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 A/C and heating system has the following features:
- The auxiliary A/C and heating system is enabled whenever the front A/C control is in any position except OFF.
- The auxiliary blower motor recirculates the air inside the vehicle. Outside air is not available to the auxiliary system.
- Air is cooled and dehumidified by the auxiliary A/C evaporator core only if the front A/C control is adjusted to a position that requires A/C compressor operation.
- The temperature blend door and the mode door are controlled by electric 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.
- Movement of the auxiliary mode control between PANEL and FLOOR causes a corresponding movement of the mode door to direct air flow between the panel (headliner) registers and the floor duct.

Blower Motor
The auxiliary air conditioning system contains a blower motor which is controlled by the heater blower motor switch on the front or rear auxiliary A/C control.

Control Assembly
The auxiliary A/C system has dual controls for the driver and rear passengers consisting of temperature, blower speed, and mode. The front auxiliary A/C control is mounted in the overhead console. The rear auxiliary A/C control is mounted in a separate overhead console positioned on the headliner.

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 from the blower motor.

A/C Evaporator Core

NOTE: If an evaporator core leak is suspected, the evaporator core must be vacuum leak tested before it is removed.

The A/C evaporator core is a plate/fin type used to remove heat and humidity from the blower motor airflow before it is delivered to the passenger compartment when A/C operation is selected.
- A mixture of refrigerant and oil enters the bottom of the A/C evaporator core through the A/C evaporator core inlet tube and then moves out of the A/C evaporator core through the A/C evaporator core outlet tube.
- All airflow from the blower motor passes through the evaporator core before reaching the heater core.

Thermostatic Expansion Valve
An thermostatic expansion valve (TXV) automatically regulates the flow of refrigerant into the auxiliary A/C 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 TXV. This temperature variation regulates the refrigerant flow to the auxiliary A/C evaporator core.
- When the bulb senses a high temperature, the TXV opens and floods refrigerant through the auxiliary A/C evaporator core.
- When the bulb senses a low temperature, the TXV starts closing to shut off the refrigerant to the auxiliary A/C evaporator core.

Underbody A/C-Heater Lines
The four auxiliary lines are one-piece tubes that are secured to the underbody of the vehicle. New auxiliary line kits are only available as two-piece lines for ease of installation.