Power Door Locks
The BCM controls the door locks by using a series of 3 (4 if equipped with rear cargo doors) integral relays. A driver door unlock relay that is energized to unlock the front doors, a passenger door unlock relay that is energized to unlock the sliding doors, a cargo door unlock relay that is used to unlock the rear cargo doors and an all lock relay that is energized to lock all the doors. When the relays are not energized, ground is provided on both circuits to the lock motors within the latches. When an unlock relay energizes, voltage is provided to one side of the lock motor to unlock the door(s). When the lock relay energizes, the polarity is reversed and the motors lock the doors.
The BCM sends voltage signals to the door lock control switches to monitor the lock and unlock requests. 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 BCM detects the lock/unlock feedback input change state and correspondingly locks or unlocks all the other 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 switches and the RKE transmitter, the BCM energizes the appropriate relay to lock or unlock the doors.
Door Lock Indicator
The BCM monitors the door lock/unlock status by sending a voltage signal to the lock/unlock feedback switch inside each of the door latches. If equipped with rear cargo doors, the lock/unlock feedback circuit for the rear cargo doors is shared with the right sliding door. The switch is closed when the door is unlocked and open when locked. The BCM uses the input from the lock/unlock feedback switches to determine if the door lock 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.