2001 GMC Safari Owner's Manual - Page 161

Rear Air Conditioning System (Option) Air Conditioning Before using your vehicle's air conditioning, open the windows to clear the vehicle of hot air. This reduces the time it takes for your vehicle to cool down. Then keep your windows closed for the air conditioner to work at its best. You can use MAX A/C with the temperature knob in the blue area when it's really hot outside and you need to cool the inside air quickly. MAX A/C lets in only a little air from the outside. If you first use MAX A/C, you can then use A/C with the temperature knob in the blue area as soon as the vehicle has cooled down, so outside air will be going through your vehicle. You may have rear air conditioning. The rear air conditioning thumbwheel is located to the right of the heater controls. Turn the thumbwheel toward HIGH for higher airflow in the rear area. Turn the switch to OFF to turn the system off. If your vehicle has rear air conditioning, setting it on LOW may enhance the front A/C performance by allowing trapped refrigerant in the rear lines to circulate. The rear air conditioning system will only send cooled air if the front system is on. It can still be used to circulate air, even if the front system is off. When the air conditioning, DEFROST or BLEND is on, you may notice a slight increase or decrease in engine speed, due to compressor operation. This is normal because the system is designed to cycle the compressor on and off to keep the desired temperature. 3-5