Air-Mixing Damper Stepping Motor
Air-mixing damper stepping motor is located on evaporator case, behind glove box. See Fig 1 . There are 2 windings in stepping motor. A voltage is applied to the windings in a special order with short pulses, causing the motor to move in short steps. The direction of motor rotation can be changed. When motor is stationary, current is applied continuously to both windings to lock motor.
By sending a definite number of pulses, ACC control module knows how much the damper moves. A feedback signal to the ACC control module is not required. ACC control module calibrates position of damper by rotating it to an end position so that exact position of the damper is known.
Calibration of damper stepping motor must be carried out if the battery has been disconnected or discharged, if the ACC control module or stepping motor has been replaced, or if stepping motor damper position has been changed. See ACC CONTROL MODULE CALIBRATION under PROGRAMMING.
The air-mixing damper position is controlled by ACC control module based on mixed-air temperature sensor. In-vehicle, selected, and ambient (outside) temperatures are used to determine mixed air temperature. If air-mixing damper is at maximum cool position, and this position is insufficient to maintain selected temperature, recirculated air mode will be selected. If the selected temperature is at its highest (HI) or lowest (LO) setting, the air-mixing damper will be set to the maximum heat or maximum cool position.