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Stepping motor, left-hand air-blending flap

Stepping motor, left-hand air-blending flap


The stepping motor has two windings. The windings are energised in a special order with short pulses. This makes the motor move in short steps, which is how it got its name. The direction of rotation can be changed. When the motor is stationary, both the windings are energised continuously to lock the motor. The stepping motor does not require a feedback coupling to the control module (position sensor). By sending a known number of pulses, the control module always knows how far the flap has moved. This is possible on condition that the control module has calibrated itself by turning the flap to its respective end positions so that it knows the position of the flap.

Calibration takes place by simultaneously pressing the AUTO and REC buttons. A sound and the message, ACC:CALIBR. STARTED are indicated in the main instrument unit, confirming the calibration. Calibration must take place if the battery is disconnected/discharged, if the ACC unit or stepping motor is replaced, or their positions are changed.

The climate system has three air-blending flaps, one for the driver's zone and one air-blending flap for the front seat passenger that is connected via a link with the air-blending flap for the rear seat passengers.

The stepping motor for the left-hand air-blending flap is supplied with current from the ACC unit's K1 pins 29 and 40 (winding 1), and K1 pins 30 and 39 (winding 2).

The flap is set by the control module using the air-blending temperature sensor for the left-hand side so that the requested air-blending temperature is obtained.

In the OFF position the flap stops in the last selected position.

When the ignition is switched off the air-blending flap will first stop in the latest selected position and after 8 minutes it moves to park position, max. cold (0%).

Diagnostics

In the event of open circuit or short circuit diagnostic trouble code B2490 is generated.

The diagnostic tool shows 100% at max. heat and 0% at max. cold.