Climate Control Panel

OFF

The blower and compressor are always "OFF" in this position. Air flows through the evaporator and heater core and is discharged into the passenger compartment from the heater outlet when the vehicle is moving. While the vehicle is standing, no air is circulated through the system. The temperature of the air is modulated to maintain the temperature selected on the control head. The ability of the system to maintain this temperature in warm weather is severely restricted since the blower and compressor are disengaged at this setting.



ECONOMY

Outside air is circulated through the evaporator and heater core and discharged into the passenger compartment from the air conditioning or heater outlets. Since the compressor is disengaged at this setting, the ability of the system to maintain the selected temperature is restricted.

Variable blower speeds are available in the ``ECON'' and ``Auto'' modes of operation. If the vehicle interior is significantly hotter or colder than the set temperature, the blower will start at high speed and hen gradually decrease to low speed as the pre-selected temperature is approached.

The economy setting is designed to maintain comfort at ambient temperatures below 70 degrees F without the compressor operating. If the engine is cold and the system is operating in heater mode, the blower will be delayed in turning on until coolant temperature increases above 95 degrees F.



LO

At this setting, operation is the same as that provided at ``Auto'' except that the blower operates at a fixed low speed.



AUTO

When the control head is in the ``Auto'' mode, the temperature control system automatically controls compressor operation, blower speed, system on air temperature, and air delivery modes.

If the vehicle interior is significantly hotter or colder than the temperature selected on the control panel, the blower will start at a high speed and gradually decrease to a low speed as the set temperature is approached.

Discharge air is delivered to the passenger compartment in three different modes: heater, air conditioning or intermediate. The discharge air is varied automatically by the air mix door between 45 degrees and 150 degrees depending on the in-vehicle temperature and the temperature selected on the ECC control panel.

If the discharge air temperature is above 95 degrees F in the heater mode the air is delivered primarily from the heater outlet. There will also be a small amount of bleed through the defroster outlets. When the engine coolant is cold the blower will be delayed from engaging until the coolant temperature reaches between 95-104 degrees F. The mode door is in the closed position.

When in the A/C mode, if blower operation is required the blower motor will turn on immediately even if the engine is cold. If the temperature in the vehicle and the temperature selected are similar, the blower operation would not be required even though in the A/C mode. The discharged air will be below approximately 83 degrees F and the mode door is in the open position.

Intermediate mode occurs when changing from the heat to A/C mode or when changing from A/C to heat mode. When switching from the heat to A/C mode, the intermediate mode occurs when the heater discharge air reaches 95 degrees F. When switching from the A/C to heat mode, the intermediate mode occurs when the A/C discharge air reaches approximately 83 degrees F. During the intermediate mode the mode door is closed and the defroster door is in the full open position forcing the air from the defroster outlets at a fixed low blower speed. There might be a minimal amount of air bleed out the heater outlet.

When the ambient temperature is above 32 degrees F, the compressor operates to dehumidify the air even though it is not required for cooling.

If the climate control system is required to operate at maximum cooling, the air inlet door opens to provide maximum cool down by recirculating passenger compartment air. Approximately 80 per cent of the air entering the passenger compartment will be recirculated air at this time. However, there must be a signal from the programmer circuit board to engage the compressor in order for the air inlet door to open. The heater hot water valve is also closed to block hot coolant flow through the heater core, which will permit quicker cool down.



HI

Operation at this setting is identical to that provided at ``Auto'', except that the blower operates at a fixed maximum speed. Recirculated air is used when maximum cooling is required. This setting is provided for quickest possible cool down under extremely hot ambient conditions. The heater water valve is also closed to block coolant flow through the heater core when in maximum cooling.




DEFROST

At this setting, most of the air is delivered to the windshield and the remaining amount of air is delivered to the heater outlet. Although the blower operates at a fixed high speed, temperature regulation is maintained. The air inlet door is closed (no vacuum), therefore, the system uses outside air.