Trunk / Liftgate Motor: Description and Operation

Fig.6 Power Liftgate Components:

LIFTGATE MOTOR
Vehicles equipped with a power liftgate, utilize a liftgate gear motor assembly. The gear motor assembly consists of a DC motor, hall effect sensor, engage actuator, full open switch, lift gear, aluminum housing, drive gears and wire harness. The gears and motor portion of the assembly provides the power and torque required to open or close the liftgate under the worst case conditions. The hall effect sensor is used to provide the liftgate control module with a speed reading, which is used to monitor the resistance of liftgate travel. This speed reading also allows the power liftgate control module to detect obstructions and move the liftgate accordingly. The engage actuator is used to toggle between power open/close mode and full manual mode when desired. The full open switch is used to let the power liftgate control module know when the liftgate is approaching the full open position.

Serviceable components of the power liftgate gear motor assembly are the complete gear motor assembly, motor and wire harness, lift gear and control rod, engage actuator, full open switch and the transverse bracket. Refer to additional information for more component details.

With the push of a power liftgate command switch (liftgate closed), the power liftgate control module will signal the latch assembly to release the door from its primary closed and latched position to the released and movable position. The liftgate motor mounted, engage actuator then engages the liftgate motor assembly, which moves the liftgate into the open position. The liftgate motor provides the torque and power to move the door to its full open or closed position (Refer to POWER DOORS - OPERATION) for additional information.

Fig.7 Liftgate Gear Motor Assembly:

ENGAGE ACTUATOR
Vehicles equipped with a power liftgate utilize a power liftgate engage actuator. The 12 volt engage actuator provides the engagement and disengagement of the liftgate gear motor to the lift gear by way of an over center link, activated by a lever.

The engage actuator is a serviceable component and cannot be repaired, if found to be faulty it must be replaced.

The engage actuators normal position is disengaged. When a power liftgate open or close command is generated from any of the command switches, the power liftgate control module signals the engage actuator to move its lever to the engaged position. This engages the gear motor to the lift gear, so when the motor turns the lift gate moves upward or downwards depending on its current position.

During a manual liftgate open or close cycle the engage actuator is disengaged, allowing unrestricted liftgate movement.