1998 GMC Jimmy Owner's Manual - Page 156

With the automatic setting,the air conditioning compressor automatically cycleswhen 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 temperatureapproaches a desired setting, the blower speed will decrease. To maintain interior comfort, the aifflow will adjust between the instrument panel air outlets and floor outlets. On bright sunny days in cool weather, the airflow may come out of the air conditioningand floor outlets (bi-level mode) to maintain comfort and prevent stuffiness. Be careful not to put anything over the solar sensor located around the center of the instrument panel. This sensor is used by the automatic system to regulate temperature. Mode Knob Manual Operation The right knob on the control panel allows you to choose the direction of air delivery. You can choose to set the climate control system operations yourself, or let the system work for you by placing the system in AUTO mode. See "Mode Knob - Automatic Operation" earlier in this section. - 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 time the 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. If your vehicle is sitting out on a warm day and you have the fan set on AUTO, the air will first flow out of the floor air outlets for a seconds. That is normal. few This is to expel hot air from the air outlets. As the air is cooled, the airflow will move through the air conditioning outlets. / PANEL: This setting directs most of the air I through the instrument panel outlets and a small amount through the floor outlets. +e BI-LEVEL: Air is delivered through the heater floor outlets as well as the instrument panel outlets. +/I +e + setting directs most of the HEATER:' This warmed air through the heater flooroutlets and some air through the windshield defroster outlets. 3-5