CL TYPE S V6-3.2L SOHC (2001)
Control Assembly: Description and Operation
How the Climate Control Circuit Works
The climate control unit controls the blower controls, air delivery, and A/C compressor controls either automatically or semi-automatically. The control
unit receives battery voltage at all times through fuse 13. With the ignition switch in ON (II), battery voltage is supplied through fuse 3. The control unit
is grounded at G401.
Fully-automatic Operation
To put the climate control in fully automatic mode, press the AUTO button and set the fan control dial to AUTO, then set the desired temperature by
turning the temperature control dial. You will see FULL AUTO in the system's display.
The system automatically selects the proper mix of cooled and/or heated air that will, as quickly as possible, raise or lower the interior temperature from
its current level to the set temperature. The system also adjusts the fan speed and changes direction of air delivery.
When you set the temperature to its lower limit (60 °F/18 °C) or its upper limit (90 °F/32 °C), the system runs at full cooling or full heating only. It does
not regulate the interior temperature. When the temperature is set between the lower and upper limits, the system regulates the interior temperature to the
set value.
Semi-automatic Operation
You can manually select various functions of the climate control system when it is in FULL AUTO. All other features remain automatically controlled.
Making a manual selection causes the word FULL to go off.
However, when you select A/C OFF, the system cannot regulate the inside temperature if you set the dial lower than the temperature outside.
Blower Controls
The fan speed is automatically controlled in the fully-automatic mode. You can manually select the fan speed by turning the fan control dial clockwise,
just past the AUTO position. This takes the fan from automatic mode to its lowest manually controlled speed. Turning the dial further clockwise
increases the fan's speed, which increases air flow.
Battery voltage is applied through fuse 56 to the blower motor relay contacts at all times. With the ignition switch ON (II), the blower motor relay in the
under-hood fuse/relay box is energized which feeds battery voltage to the blower motor. The blower power transistor controls the blower motor in all
speeds except HIGH. The blower power transistor is controlled by the climate control unit. When the control unit requests HIGH blower speed, it
grounds the blower motor HIGH relay coil, energizing the relay, which connects the blower motor directly to ground, making the blower run at high
speed.
In cold weather, the blower will not come on automatically until the heater starts to produce warm air.
Air Delivery
The climate control unit controls the blower motor and supplies a 5 VDC reference voltage to the air mixture control motor.
The air mix and mode control motors each receive inputs from the control unit. The air mix motor regulates the mixture of cold and hot air by varying
the position of the heater-evaporator door. The mode control motor controls the direction and volume of outlet air. Use the MODE button to select the
vents the air flows from. Some air will flow from the dashboard corner vents in all modes. Each time you press the MODE button, the display shows the
mode selected. Press the button four times to see all the modes. Both the air mix control motor and mode control motor are grounded by the control unit.
The recirculation control motor receives battery voltage through fuse 3 when the ignition switch is ON (II). It regulates the position of the fresh/recirc
door, and is controlled by two position inputs from the control unit ("Recirc" and "Fresh").
A/C Compressor Controls
Voltage is provided at all times to the A/C compressor clutch relay contacts through fuse 59. with the ignition switch ON (II), voltage is supplied to the
relay coil through fuse 3.
With the ignition switch ON (II), the climate control unit grounds the A/C ON input of the PCM through the A/C pressure switch. The PCM then
grounds the A/C compressor clutch relay coil. This energizes the coil, which closes the relay contacts and provides voltage through fuse 59 to the A/C
compressor clutch. The clutch then engages and begins turning the compressor. By default, when the climate control system is on, the A/C is also on.
Evaporator Temperature Sensor
The evaporator temperature sensor is located on the evaporator housing. If the temperature at the evaporator gets too cold, the evaporator temperature
sensor sends a signal to the climate control unit to turn off the A/C compressor clutch. This prevents condensation from freezing on the evaporator fins
