AUTOMATIC AIR CONDITIONING SYSTEM : Motor Zero Position Reset

A step motor is used for the mode door motor and air mix door motor. Because the step motors do not have position detection mechanisms, there may be a deviation between the door position recognized by the A/C auto amp. and the actual door position. Therefore, the A/C auto amp. per-forms motor zero position reset in order to align its recognized door position with the actual door position. When either of the conditions below is satisfied, the A/C auto amp. performs motor zero position reset when the power switch next turns ON or when pre-A/C turns ON.
-The 12V battery terminal is disconnected and then is reconnected.
-The power switch is turned OFF during operation of the mode door motor or air mix door motor a total of 60 times. During zero position reset operation, the DEF switch indicator flashes for several seconds. No switch opera-tions are accepted during this tim