The power door locks system consists of the following components:

The power door lock system is controlled by the BCM and can be activated by any one of the following:

For door lock operation, the IP Fuse Block supplies battery positive voltage, through the 15 amp DR LK/TRUNK fuse, to the BCM. The BCM uses this circuit exclusively to apply power to the door lock actuators. The BCM is also supplied a ground circuit, which it uses exclusively to ground the door lock actuators. When a door lock is pulsed, the BCM internally connects these two circuits to the appropriate lock and unlock control circuits to actuate the locking or unlocking functions.

When diagnosing door lock malfunctions, these circuits must not be confused with the other battery voltage and ground circuits of the BCM. The appropriate wiring schematic must be used to locate the correct circuits. Failure to identify the correct battery voltage and ground circuits of the BCM during diagnosis of door lock concerns may result in misdiagnosis and unneccessary parts replacement.

When the BCM detects a transition of either of the door lock switches to the Lock position, it switches the door lock actuator lock control circuit to voltage. Since the lock actuator unlock control circuits are at ground potential within the BCM, all the door lock actuators transition to the Lock position.

When the BCM detects a transition of either of the door lock switches to the Unlock position, it switches the driver door lock actuator unlock control circuit to voltage. Since the door lock actuator lock control circuit is at ground potential within the BCM, the driver door lock actuator transitions to the Unlock position.

The driver door lock actuator unlock control circuit is a dedicated control circuit used only for the driver door lock actuator. This is done so that the driver door may be unlocked individually before unlocking the passenger doors using a keyless entry transmitter or an automatic door unlock function, if programmed.

When the BCM detects a transition of either of the door lock switches to the Unlock position, it switches the door lock actuator unlock control circuits to voltage. Since the door lock actuator lock control circuit is at ground potential within the BCM, the passenger door lock actuators transition to the Unlock position.

The door lock actuator unlock control circuits are dedicated control circuits used only for the passenger door lock actuators. This is done so that the driver door may be unlocked individually before unlocking the passenger doors using a keyless entry transmitter or an automatic door unlock function, if programmed. When the keyless entry transmitter is used to unlock the passenger doors, the BCM requires a repeated unlock command before it performs the unlock function. However, when the unlock input is from a door lock switch, a single unlock command is all that is required to unlock all doors.

The automatic door lock/unlock function is a Vehicle Personalization feature with the following 4 programmable modes of operation:

The automatic door lock function can only be enabled by the BCM if the driver door switch is in the Inactive state, meaning the door is closed. For information on programming the automatic door locks, refer to Vehicle Personalization in Personalization.

This function is intended to prevent the vehicle operator from locking the doors if the key is left in the ignition and the driver door is open. The lockout prevention function can be overridden by the BCM if the BCM receives a door Lock input for longer than 3 seconds.

The LDCL function is a Vehicle Personalization feature that is intended to allow the doors to be locked while passengers are exiting the vehicle. When LDCL is in Active Mode, the BCM will delay locking of the vehicle doors for 5 seconds after all of the doors have been closed. The LDCL function will be overridden if the BCM receives a door Unlock input or a key in ignition input.

The BCM will lock all of the doors immediately upon detecting a door lock cylinder switch in the Lock position. The BCM supplies battery positive voltage, through the door lock key switch lock signal circuit, to the door lock cylinder switch. The door lock cylinder switch is grounded, through the ground circuit, to a body ground stake. When the door lock cylinder switch is activated to the Lock function, the normally open contacts of the two circuits are closed, and the BCM interprets the flow of voltage as a lock doors input.

The BCM will unlock all of the doors after detecting a door lock cylinder switch in the Unlock position for greater than 1 second. The BCM supplies battery positive voltage, through the door lock key switch unlock signal circuit, to the door lock cylinder switch. The door lock cylinder switch is grounded, through the ground circuit, to a body ground stake. When the door lock cylinder switch is activated to the Unlock function, the normally open contacts of the two circuits are closed, and the BCM interprets the flow of voltage as an unlock doors input.