Shift Motor/Mode Sensor
ASSEMBLY-SHIFT MOTOR/MODE SENSORDESCRIPTION
The shift motor (1) is an electromechanical device consisting of a DC permanent magnet motor, a motor brake, a gear train and an analog position sensor. The shift motors' overall function is to move and lock a gear that moves the mode fork found in the transfer case. This allows the transfer case to be shifted electrically to multiple operating positions (4LOCK and AWD). The operating current of the shift motor under stall conditions is 30 amps maximum at 72°F with 13.5 volts, at the motor leads.
OPERATION
Shifting in the transfer case occurs when the shift motor brake is released and a Pulse Width Modulated (PWM) voltage is supplied to the shift motor by the Front Control Module (FCM). A linear analog position sensor located inside the shift motor, provides the FCM with the motors' angular, rotational position. With this information, the FCM continuously knows the motors' position, and therefore allows it to accurately control the motors' operation, including voltage polarity which is used to control motor direction.