1995 GMC Yukon Owner's Manual - Page 164

fuel economy. This setting also cools the air the fastest and can be used to keep "unwanted odors" and/or dust from entering the vehicle. When using the air conditioner, turn off recirculation after the vehicle reaches a comfortable interior temperature. When the right knob on the control panel is between HEAT and DEFROST, the recirculation feature will not function. A/C This button, between the middle and right knobs, allows the air coming into your vehicle to be cooled and directed through the instrument panel vents. This setting is useful for normal cooling on hot days. When you first use A/C with the recirculation button pushed in, turn off recirculation as soon as the vehicle reaches a comfortableinterior temperature. - Engine Coolant Heater If your vehiclehas a diesel engine, it is equipped with an engine coolant heater. An engine coolant heater is optional on gas enginevehicles. If you use the engine coolant heater before starting your engine (in cold weather (20" F, (-8" C ) , or lower) your heating system will produce warmer air faster, to heat the passenger compartment in cold weather. The use of an engine coolant heater also reduces the time it takes for the engine to reach normal operating temperature, and shortens the time it takes the heater to reach full output. For more information, See "Engine Coolant Heater" in the Index. Diesel Engine Heater Output If you idle your diesel engine for along time when it's cold outside, your heater may blow out cool air. This is normal. When you increase the engine speed, your heater should blow out warmer air. If it doesn't, your coolant level may be too low. See "Engine Coolant" in the Index to see how to check your coolantlevel. Rear Air Conditioning and Heating Systems (Suburban) If your vehicle has either orboth of these systems, you can increase and decrease the air flow at the rear vents. Depending on the system you have and the setting selected, you can send cooled or heated air to the rear of the vehicle. Rear Air Conditioning (Without Rear Heater) If your vehicle has rear air conditioning (without rear heater), the controls are located above the front and second seats. The front and rear overhead controls let you increase and decrease the air flow at the rear vents. 3-4