GM Service Manual Online
For 1990-2009 cars only

Recirculation/Fresh Air Control

Outside Air Button

When the outside air button is pressed, air from outside of the vehicle is drawn into the evaporator and heater core module and heated or cooled depending on what temperature is set. Air can be discharged from the air conditioner, heater and defroster outlets.

Recirculate Air Button

When the recirculate air button is pressed, air from inside the vehicle is mixed with a small amount of outside air. The air is discharged from the air conditioner, heater and defroster outlets.

A/C Button

When the A/C button is pressed, the A/C compressor is turned on or off under most conditions. The light on the A/C button comes on when the compressor is operating. The A/C compressor does not operate at temperatures below approximately 2° C to 4° C (35° F to 40° F). Pressing the A/C button while the A/C compressor is on will turn the A/C compressor off.

Temperature Control Knob

The temperature control knob controls the temperature of the air coming through the system. Turning the knob to the right (toward the red area) for warmer air. Turning the knob to the left (toward the blue area) for cooler air. The temperature control knob is located in the center of the heater and A/C control head.

Upper


Object Number: 82115  Size: SH

This setting directs most of the air through the instrument panel outlets and a very small amount to the lower outlets.

Bi-Level


Object Number: 82117  Size: SH

This setting directs air into the vehicle in two ways. Cooler air is directed toward the upper body through the instrument panel outlets, while warmer air is directed through the lower outlets.

Lower


Object Number: 82114  Size: SH

This setting directs most of the air to the floor area and some of the air toward the windshield and side window vents.

Defog


Object Number: 82112  Size: SH

This setting divides the air between the windshield and lower outlets and a small amount toward the side window vents. This is useful fog appears on the windshield or side glass due to rain or snowy conditions.

Front Defrost


Object Number: 82120  Size: SH

Press the FRONT defrost button to quickly remove fog or frost from the windshield. This setting directs most of the air flow to the windshield and a small amount toward the lower and side window outlets. The light on the button will come on and the digital display will show the defrost mode symbol an fan speed when the front mode is being used. Pressing FRONT defrost again will return the system to the last operating mode.

If the system is in FRONT defrost when the engine is shut off, it will restart in FRONT defrost unless the engine is off for longer than 40 minuets. If the engine is off longer than 40 minuets, the system will restart in the operating mode that was set prior to FRONT defrost.

Blower Speed Control

The fan control knob is located on the left of the heater and A/C control head. The fan control knob turns the blower motor off when the OFF position is selected. Turning the knob to the right increases the blower motor speed. The blower motor must be on for the A/C compressor to operate.

Rear Defrost Button

Pressing the REAR DEFROST button will turn on the rear defroster. The first time the button is pressed will operate the rear defroster for 10 minutes. Pressing the REAR DEFROST button after the first 10 minutes of operation will allow five more minutes of operation. If the button is pressed during rear defroster operation, the defroster will turn off. The REAR DEFROST button also activates the heated mirrors.