1999 Pontiac Grand Prix Owner's Manual - Page 157

yellowblue Automatic Control For the most efficient operation, you should set the system temperature and press AUTO. The system will select the best fan speed and airflow settings to keep you comfortable. The air conditioning compressor will run if the outside temperature is above 38_F (3.3_C). You may notice a delay of three to four minutes before the fan comes on. Driver's Temperature Knob The left knob sets the temperature for the entire system when the light on DUAL button isn't lit. If the light is lit, the knob sets the temperature for the driver. Turn the knob toward red (clockwise) to raise the desired cabin temperature. Turn it toward blue (counterclockwise) to lower the temperature. The display will show your selection for a few seconds, then the outside temperature will show or be displayed. Passenger's Temperature Knob The right knob sets the desired cabin temperature for the passenger and will automatically force the system into a dual zone operation, lighting the dual zone button light. Turn the right knob toward red (clockwise) to raise the temperature. Turn it toward blue (counterclockwise) to lower the temperature. Dual Zone Button Light The dual zone button light indicates whether the system is in single zone or dual zone operation. When there is no desire for dual zone operation, push the lit dual zone button to return to single zone operation. The dual zone button light will go off. The system will operate to achieve your comfort set point as quick as possible. If you set the temperature for 60_F (16_C) or 90_F (32_C), the fan will go to its highest speed, unless you manually select a lower speed. The system will maintain full cold or full hot operation at these settings. Cold Weather Example: When you start the vehicle in cold weather, (below freezing) or after being parked overnight. If your Driver Set Temperature is 73_F (23_C) and you are in Full Automatic mode, the system will automatically move the temperature doors to full hot. The blower will start out at a low speed and the blower speed will increase as the engine warms up. The air will be delivered to the floor. As the interior of the vehicle warms up to your desired comfort point, the blower will decrease and the temperature door will move to a cooler position to maintain your desired comfort. As the cabin warms up or the sun load increases the system could switch to air delivered to the individual to the windshield and the floor (Defog mode). 3-5