Circuit/System Description

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The power liftgate module (PLGM) controls operation of the liftgate latch motor and the liftgate actuator assembly. Under normal conditions the power latch can only be unlatched under power from the PLGM through an input from the liftgate handle switch, the overhead console switch, or the remote keyless entry (RKE) transmitter, but the liftgate may be manually closed to the primary latched position without the PLGM performing the power latch function. The ON/OFF switch in the overhead console will enable or disable the power open/close operation of the actuator assembly and have no effect on power latch operation. The liftgate actuator assembly consists of the actuator drive motor with 2 internal hall effect sensors. The drive motor is mated to a worm type gear off the actuator clutch and when the clutch is engaged the motor rotation is transferred to the clutch gear, intermediate gear, and actuator arm gear. The full open switch is a limit switch mounted on the liftgate actuator assembly along side the actuator arm gear, and will make contact with the cam on the actuator arm gear when the liftgate is near the full open position. The PLGM continuously monitors the liftgate location and direction of travel using the 2 hall effect sensors in the drive motor. The sensor counts are used to determine when the liftgate has reached the open and closed points of travel where the actuator clutch should be disengaged. These positions may vary slightly and must be learned when most liftgate components are serviced.