System Description
System OperationThe electronic climate control system automatically maintains the temperature selected for driving comfort and regulates the airflow between the instrument panel A/C registers, heater outlet floor ducts, windshield defroster hose nozzles and A/C side window demisters. The system also provides the option of manually overriding the heater blower motor speed and/or airflow direction as desired. Additionally, the system has automatic compensation for high sunload conditions. This results in cooler interior temperatures. The A/C sunload sensor is located in the upper RH corner of the instrument panel near the defroster grille. For optimum automatic operation, the system should be in AUTOMATIC mode and set to the desired temperature setting. If the vehicle interior temperature is warmer or cooler than the set temperature, the climate control system will automatically provide heat (when the engine is warm) or air conditioning, as required, to reach the comfort setting as quickly as possible. If it is necessary to adjust the comfort setting, the setting should be changed only in small increments (1-2 degrees) to maintain comfort and avoid large variations of in-vehicle temperature. Raising or lowering the set temperature in large increments from the comfort setting will not reduce the time required to reach stabilized comfort.
The numbers in the Control Assembly Operational Diagram are referenced in the following text.
AUTOMATIC
Pressing the AUTOMATIC button turns the system on for fully automatic operation. When functioning automatically, the VFD window will be lighted to show the selected temperature. The system will maintain this temperature by controlling the airflow direction (functional setting), the airflow quantity (fan speed) and the discharge temperature required for comfort. When heating is required, the airflow will automatically be directed through the floor ducts and demisters with a small amount of air through the windshield defroster hose nozzle. During cool weather, the fan operation will be delayed until the engine has heated sufficiently to provide warm discharge temperatures.
When cooling is required, the airflow will be directed through the instrument panel registers. The A/C registers can be adjusted for optimum comfort. When maximum cooling is required, the system will automatically operate with recirculated air for rapid cool-down and automatically change to outside air as the vehicle interior approaches the selected temperature.
In moderate conditions, the system will automatically operate in a split manner, with airflow directed through the heater outlet floor ducts and through the windshield defroster hose nozzle at a moderate fan speed.
OFF
Pressing the OFF button will turn the system off completely and display the word OFF in the digital display window.
Digital Display Window
The digital display window will indicate one of two displays depending upon the manual selection:
1. Selected function/comfort temperature
2. OFF when the system is off
Warmer (RED) Button
The red button is used to raise the temperature setting. Press the button once to raise the temperature one degree. Holding the button in will continuously raise the temperature setting in one-degree increments to 29°C (85°F) and then will jump to 32°C (90°F) in one step for continuous maximum heating.
Cooler (BLUE) Button
The blue button is used to lower the temperature setting. Press the button once to lower the temperature one degree. Holding the button in will continuously reduce the temperature setting in one-degree increments to 18°C (65°F) and then will jump to 15°C (60°F) in one step for continuous maximum cooling.
Rear Fan Off
Pressing this button will stop operation of the rear blower assembly. It will not permit rear blower operation until it is pressed a second time.
Manual Overrides
There are six manual override buttons along the lower edge of the control assembly. Each affects system operation as follows:
MAX A/C
Pressing the MAX A/C button will display "60 MAX A/C" in the display window. The system will go to high blower motor operation with a maximum cool discharge temperature while also going into recirculation function (which uses air from inside the vehicle).
Vent
Pressing the VENT button will display "VENT" in the display window. The system will operate with outside air in the panel function. The A/C clutch will be off.
PNL-FLR
Pressing the PNL-FLR button will display "PANEL FLOOR" in the display window. The air will be discharged equally between the panel and the floor.
FLOOR
Pressing the FLOOR button will display "FLOOR" in the display window. The majority of the air distribution will be directed through the heater outlet floor ducts with a small bleed to the A/C side window demisters and the windshield defroster hose nozzle.
FLR-DEF
Pressing the FLR-DEF button will display "FLOOR DEFROST" in the display window and air will be distributed equally between the windshield defroster hose nozzle and the heater outlet floor ducts with a small bleed to the A/C side window demisters.
Defrost
Pressing the defrost button lights the DEFROST indicator and directs the majority of the airflow through the windshield defroster hose nozzle, with a small bleed to the A/C side window demisters and the heater outlet floor ducts.
Blower Speed Override Thumbwheel
Rotating the blower speed override thumbwheel more than 10 degrees will turn on the automatic blower indicator and provide manual control of the blower motor speed. Rotating the wheel fully down against its lower stop locks the blower at its lowest speed. Rotating the wheel fully up against the stop locks the blower at its highest speed.
Pressing the AUTOMATIC button will resume automatic blower control and the AUTOMATIC blower indicator light will turn on.