Power Door Locks

The BCM controls the door locks by sending messages over the CAN to the DDM and the PDM. The DDM and the PDM each relay the message over a LIN to the Driver Rear Door Module (DRDM) and the Passenger Rear Door Module (PRDM) respectively. Each door module supplies power and ground to its corresponding door lock actuator (integrated into the door latch). The modules reverse the polarity to switch between the lock and unlock functions.

For vehicles equipped with rear cargo doors, the BCM controls the rear cargo door lock by using a series of 2 integral relays. When the relays are not energized, ground is provided on both circuits to the lock motor within the latch. When the unlock relay energizes, voltage is provided to one side of the lock motor to unlock the rear cargo door. When the lock relay energizes, the polarity is reversed and the motor locks the door.

The BCM sends voltage signals to the door lock control switches. When a door lock control switch is pressed, the voltage signal is routed to ground, indicating a request to lock or unlock the doors.

The doors can also be centrally locked or unlocked using a key in the driver door lock cylinder. When a key is used in the driver door lock cylinder to lock or unlock the driver door, the DDM detects the lock/unlock feedback input change state and sends a message to the BCM indicating the lock/unlock status of the driver door. The BCM correspondingly sends a command over the network to the DDM and the PDM to lock or unlock the doors.

In the event of a failure of the power door locks, the doors can be individually locked using the manual door lock. The manual door lock is located on the rear edge of the door just above the door latch opening. For the doors on the left side of the vehicle, insert a key and turn the key clockwise to lock. For the doors on the right side of the vehicle (or the rear cargo door if equipped), insert a key and turn the key counterclockwise to lock.

Based upon input from the door lock control switches, the lock/unlock feedback input and the RKE transmitter, the BCM unlocks the driver door, unlocks all the doors or locks all the doors.

Based upon input from the door lock control switches, the lock/unlock feedback switches and the RKE transmitter, the BCM commands the door to lock or unlock.

Door Lock Indicator 

Each door module monitors the door lock/unlock status by sending a voltage signal to its corresponding lock/unlock feedback switch inside each door latch. The switch is closed when the door is unlocked and open when locked. The rear door modules send the information to the corresponding front door modules. The front door modules then transmit the door lock/unlock status to the BCM.

For vehicles equipped with rear cargo doors, the BCM monitors the rear cargo door lock/unlock status by sending a voltage signal to the lock/unlock feedback switch inside door latch. The switch is closed when the door is unlocked and open when locked.

The BCM uses the input from the lock/unlock feedback to determine if the indicator should be illuminated or off. The BCM controls the voltage to the door lock indicator.

If all the doors are locked and the liftgate (if equipped) are closed, the indicator is illuminated. If any door is unlocked or the liftgate is open, the indicator is off. If the ignition is off when all the doors are locked and the liftgate (if equipped) is closed, the indicator turns off after approximately 5 minutes have elapsed.

Reverse Door Lock Cycling 

The reverse door lock cycling feature provides audible feedback by unlocking the doors if one of the front doors or the rear cargo door is ajar after receiving a lock request.

The BCM also activates the reverse door lock cycling feature if a short to ground (stuck closed switch) fault is present from any of the unlock feedback circuits.

The rear door reverse lock cycling for the rear door can only be enabled or disabled using a diagnostic scan tool. Vehicles come from the factory with this feature enabled.