GM Service Manual Online
For 1990-2009 cars only

Heater and A/C Control Assembly


Object Number: 246913  Size: SF

The heater and A/C control allows the vehicle operator to communicate with the electronic A/C system. The heater and A/C control includes the following features:

    • Soft touch buttons to select operating modes
    • A temperature control
    • A fan speed control
    • A rear window defogger
    • A vacuum florescent (VF) information display panel

Each operating mode button (except OFF) contains an LED indicator that illuminates when the operator selects that mode. The rear window defogger also has an LED indicator.

The heater and A/C control assembly includes a vacuum-fluorescent display.

Temperature Button

The temperature control performs the following functions:

    • When the system is in the OFF mode, the system turns ON in the AUTO mode when the occupant of the vehicle presses temperature UP or DOWN button.
    • When the system is in any mode except OFF, either button performs one of the following actions:
       - If the temperature is 19°-29°C (66°-84°F), pressing WARM/COOL buttons increases/decreases the internal temperature setting by 1°.
       - If the temperature is 18°C (65°F), pressing the COOL button decreases the internal temperature setting to 16°C (60°F).
       - If the temperature is 30°C (85°F), pressing the WARM button increases the internal temperature setting to 32°C (90°F).

A change is the temperature setting signals the heater and A/C programmer to bring the passenger compartment temperature to the new setting. This is done by changing the following items:

    • The blower speed
    • The air discharge location
    • The air discharge temperature

Fan Speed

Use the fan speed button in order to manually change the fan speed in the following manner:

    • Pressing the fan speed button once increases/decreases the fan speed by 1 level.
    • Holding the fan speed button will increase/decrease the fan speed to the maximum speed.

If the system is operating under AUTO fan speed control, pressing the stops the AUTO fan speed control and begins a manual fan speed control.

The fan speed remains constant, unless the driver presses one of the speed control buttons again.

When the system is in OFF mode, pressing the AUTO button causes the system to turn on AUTO mode with AUTO fan speed control.

Mode Selector Buttons

The heater and A/C control has a mode selector button for each of the following operating modes:

    • OFF
    • AUTO
    • AIR FLOW
    • VENT
    • RECIRC
    • FRONT DEFROST
    • REAR DEFOG

If the driver presses AUTO, the following actions occur:

    • The heater and A/C programmer tests the internal temperature selected by the operator and the information provided by the system's network of sensors.
    • The heater and A/C programmer then initiates the appropriate air intake point, air discharge points and activates/deactivates the A/C compressor

AIR FLOW

Use the AIR FLOW button in order to change the air flow direction in the vehicle. Selection of the AIR FLOW button when in AUTO mode will lock in the air flow direction that AUTO was controlling. Pressing the AIR FLOW button also activates the VF display for the direction selected. If an air flow direction is currently displayed, pressing the AIR FLOW button selects the next air flow direction, either up or down depending on operator selection. The air flow direction will sequence upward through the following modes:

  1. FLOOR
  2. FLOOR/MID
  3. MID
  4. WINDSHIELD/FLOOR

The downward sequence is the reverse of the upward sequence. These are the only air flow direction s available through the AIR FLOW button.

VENT

When the driver presses the VENT button, the VENT LED illuminates and the system requests that the A/C compressor be turned OFF.

    • The VENT LED illuminates.
    • The system will request that the A/C compressor to be turned off.

The driver may not activate both VENT and RECIRC at the same time.

The VENT button has no effect on the system when the FRONT DEFROST mode is selected.

RECIRC (Recirculate)

The main function of the RECIRC button is to limit the amount of outside air that is brought into the vehicle by activating the air inlet valve. When the driver presses the RECIRC button, the RECIRC LED illuminates and the system closes the recirculate door.

    • The RECIRC LED illuminates.
    • The system will close the recirculate door.

The driver may not activate both VENT and RECIRC at the same time.

The RECIRC button has no effect on the system when the FRONT DEFROST mode is selected.

RECIRC operates for approximately 10 minutes before deactivation. The driver may also deactivate the RECIRC function by changing to a manual mode.

FRONT DEFROST

When the driver pressed the FRONT DEFROST button, the FRONT DEFROST LED illuminates and the current temperature setting displays for 5 seconds.

The FRONT DEFROST directs air to the windshield. FRONT DEFROST is a manual mode only.

Vacuum Fluorescent (VF) Information Display Panel

The vacuum fluorescent (VF) panel provides system operating information for the driver. A 3-digit temperature readout is located near the center of the display. With the system in OFF mode, the outside temperature is displayed continuously.

The driver may display the current temperature setting by selecting any mode except OFF or adjusting the temperature control.

The current temperature setting displays for 5 seconds. The display then returns to the outside temperature.

Symbols

The following arrows appearing in the center of the display indicate the air discharge location relative to the seat:

    • An upper (windshield) discharge arrow
    • A lower (floor level) discharge arrow
    • A middle (instrument panel) discharge arrow

Either one or a combination of these discharge arrows may be illuminated, depending on the current system operating mode. If the system is turned OFF, the area is blank and the display returns to the outside temperature reading.

The driver may display the current temperature setting by selecting any mode except OFF or adjusting the temperature control.