1999 Cadillac DeVille Owner's Manual - Page 163

yellowblue Mode Button Press the MODE button to deliver air through the floor, middle or windshield outlets. The system will stay in the selected mode until the MODE button is pressed again. Press the up or down arrow to cycle through the available modes. Automatic Operation When the system is set for automatic operation, sensors will control the air delivery mode. Air will come from the floor, middle or windshield outlets. The fan speed will vary as the system maintains the selected temperature setting. Be careful not to put anything over the solar sensor located in the middle of the instrument panel near the windshield. This sensor is used by the automatic system to regulate temperature. To find your comfort zone, start with the 75_F (24_C) setting and allow about 30 minutes for the system to regulate. Turn the TEMP/AUTO knob to adjust the temperature if necessary. If you choose 60_F (16_C), the system will remain at that maximum cooling setting and will not regulate fan speed. If you choose the temperature of 90_F (32_C), the system will remain at that maximum heating setting and will not regulate fan speed. Choosing either maximum setting will not cause the system to heat or cool any faster. With the automatic setting, the air conditioning compressor automatically cycles when needed to cool the air. In cold weather, when the system senses the need for heat, the airflow will be directed out the floor outlets. As the interior temperature approaches a desired setting, the blower speed will decrease. To maintain interior comfort, the airflow may move to the instrument panel air outlets and floor outlets (bi-level mode). On bright sunny days in cold weather, the airflow may come out of the air conditioning outlets (AC mode) to maintain comfort and prevent stuffiness. If your vehicle is sitting out on a hot day and you have it set on AUTO, the air will first flow out the floor air outlets for a few seconds. That is normal. This is to expel hot air from the air outlets. As the air is cooled, the airflow will move through the air conditioning outlets. If you start your vehicle with the fan setting on HI, it will skip the air conditioning purge. To avoid blowing cold air in cold weather, the system will delay turning on the fan until warm air is available. The length of delay depends on the outside air temperature, engine coolant temperature or the time since the engine was last started. As the coolant warms up, the blower fan speed will gradually increase and air will flow from the heater outlets, with some airflow to the windshield to prevent fogging under most normal conditions. 3-7