Component Description
Power Liftgate Switch - Instrument Panel
The instrument panel power liftgate switch is a momentary contact switch that supplies a ground signal to the LTM when it is pressed. Pressing this switch either opens, closes or stops the power liftgate depending upon the conditions.
Power Liftgate Switch - Rear
The rear power liftgate switch is a momentary contact switch that supplies a ground signal to the LTM when it is pressed. Pressing this switch closes the power liftgate depending upon the conditions.
Power Liftgate Switch - Exterior
The exterior power liftgate switch is a momentary contact switch that supplies a ground signal to either the BCM-B (without Intelligent Access (IA)) or the RFA module (With Intelligent Access).
Without Intelligent Access (IA)
When the exterior liftgate switch is pressed, the BCM-B sends a signal to the LTM over a hardwired circuit which opens the liftgate only when the doors are unlocked.
With Intelligent Access
When the exterior liftgate switch is pressed, the RFA module activates the power liftgate Intelligent Access (IA) feature. If the conditions allow, the RFA module sends a signal over the MS-CAN to the LTM which opens the liftgate.
Pinch Strip Switch
The power liftgate pinch strips are membrane style switches. When the switch is pressed the contacts inside the switch make contact and send a ground signal to the LTM indicating that there is an obstacle preventing the liftgate from closing. When the pinch strip is not pressed, it has an approximate resistance of 2500-10, 500 ohms.
Power Liftgate Chime
The power liftgate chime provides audible warnings to the operator. It is mounted on the LTM and is not servicable separately.
The power liftgate feature sounds an audible chime for 3 seconds whenever:
- the liftgate is requested to begin power closing
- the liftgate reverses to power opening due to an obstacle
- the liftgate stops opening due to an obstacle
The power liftgate feature sounds an audible chime for 1 second whenever there is an open/close request and:
- the vehicle speed is above 5 km (3.11 mi)
- the ignition is in RUN or the transmission is not in park
- the battery voltage is low
Power Liftgate Latch
The power liftgate latch is responsible for latching, unlatching, and cinching the liftgate. The power liftgate latch contains the unlatch/cinching motor, detent switch, forkbolt primary and secondary switches, and the sector gear switches.
Unlatch/Cinching Motor
The latch uses a bi-directional motor to accomplish both unlatch and cinch operations. The motor is driven in one direction to cinch and in the opposite direction to unlatch. During a cinch operation, power is supplied to the unlatch/cinching motor by the LTM when the secondary latch position is reached during a power close operation. When the motor activates, it pulls the liftgate into the primary latch position. The LTM removes power from the unlatch/cinching motor when the primary latch position is reached. During an unlatch operation, power is supplied to the unlatch/cinching motor by the LTM when a valid open command is received.
Power Liftgate Detent Switch, Forkbolt Primary Switch and Forkbolt Secondary Switch
The power liftgate detent switch, forkbolt primary switch and forkbolt secondary switch provide inputs to the LTM to determine liftgate latch position. The liftgate is in the primary position when the liftgate is in the full closed position. The liftgate is in the unlatch position when the liftgate is open and completely out of the striker. The LTM receives inputs from the power liftgate detent switch, forkbolt primary switch and forkbolt secondary switch in the following manner:
| Latch Position | Detent Switch | Forkbolt Secondary Switch | Forkbolt Primary Switch |
|---|---|---|---|
| Fully Unlatched | Open | Grounded | Grounded |
| Secondary | Grounded | Open | Grounded |
| Primary | Grounded | Open | Open |
Sector Gear Switches
The sector gear open and close switches provide input to the LTM to determine the position of the sector gear. The sector gear is part of the latch assembly. It is driven by the latch motor and in turn drives the latch mechanism. During a release operation, the LTM deactivates the unlatch/cinching motor once the end of travel is reached. After a release operation, the LTM keeps the latch released until the gate moves away from the vehicle. The LTM then reverses the direction of the unlatch/cinching motor until the sector gear switches indicate the sector gear has returned to the neutral position. Refer to the following table for sector gear switch states:
| Sector Gear Position | Sector Gear Open Switch | Sector Gear Close Switch |
|---|---|---|
| End of Travel | Grounded | Grounded |
| Release | Open | Grounded |
| Cinch | Grounded | Open |
| Neutral | Open | Open |
Power Liftgate Motor
The power liftgate motor is responsible for raising and lowering the liftgate. The power liftgate motor is a bi-directional motor and contains a position sensor that provides input back to the LTM for liftgate position and velocity.
Position Sensor
The LTM supplies a 5-volt reference voltage to the position sensor on a valid open command or anytime the liftgate is in the open position (up to 6 hours). The LTM constantly supplies the ground. The position sensor has 2 data lines that the LTM monitors to determine liftgate movement and position. The LTM uses the liftgate position information to determine which direction to power the liftgate (open or close) when a valid operation command is received. The movement is monitored to identify obstructions.
Liftgate Or Trunk Module (LTM)
The LTM is responsible for opening or closing the power liftgate based on the inputs it receives. Based on the inputs, it determines if conditions allow a power open or power close.
The BCM-B supplies battery logic power required for the software and internal switching operations. Power is supplied to the motor and latch by BJB. Ground for the LTM is a separate single connection. Some of the continuous inputs which are at a ground state when on, are also used for logic switching.
The LTM does not require PMI when it is replaced.