GM Service Manual Online
For 1990-2009 cars only

Power Door Lock System Components

    • Remote control door lock receiver (RCDLR)
    • Driver door switch assembly (DDSA)
    • Driver door module (DDM)
    • Passenger door module (PDM)
    • Driver door lock switch
    • Driver door lock status indicator
    • Passenger door lock switch
    • Passenger door lock status indicator
    • DOOR CONTROLS circuit breaker (30-amp)
    • ACCA/DRIV DR SW fuse (10-amp)

Driver Door Lock and Unlock Operation

The driver door lock switch lock and unlock signal circuits provide input to the DDS when the driver door lock switch is activated to the Lock or Unlock position. These inputs allow the DDS to detect a door lock or unlock request. The DDS provides power to the driver door lock switch. When the driver door lock switch is activated, ground is supplied by G201. When the DDS detects low voltage on a signal circuit, the DDS will send a message on the serial data line to the Remote control door lock receiver (RCDLR) to place the driver and passenger doors in lock or unlock status, disabling or enabling the power door latch.

Passenger Door Lock and Unlock Operation

The passenger door lock switch lock and unlock signal circuits provide input to the passenger door module (PDM) when the passenger door lock switch is activated to the Lock or Unlock position. These inputs allow the PDM to detect a door lock or unlock request. The PDM provides power to the driver door lock switch. When the driver door lock switch is activated, ground is supplied by G202. When the PDM detects low voltage on a signal circuit, the PDM will send a message on the serial data line to the Remote control door lock receiver (RCDLR) to place the driver and passenger doors in lock or unlock status, disabling or enabling the power door latch.

Automatic Door Locks

The automatic door lock feature provides for the locking and unlocking of one or both of the doors automatically when shifting the transmission. When the vehicle doors are closed, ignition turned ON, and the transmission is shifted out of PARK, all doors will lock. When the vehicle is stopped and the transmission is shifted into PARK, one or both of the doors will unlock.

Operation of the automatic door lock system depends upon door status information gathered by the body control module (BCM), and examined by the remote control door lock receiver (RCDLR). The system will not operate properly if the RCDLR, which is the door lock master, detects that a vehicle door is open. Each door latch contains a door open switch. Each door open switch receives voltage from the BCM and are grounded independently. When a door is open, the switch closes, voltage flows through the switch, and the BCM interprets the flow of voltage as a door open input. The BCM sends this information over the class 2 serial data circuit where it is detected by the RCDLR. If the RCDLR determines that one of the vehicle doors is open, automatic door locking will not be permitted.

Automatic door locking is programmed during the manufacturing process, but it can be custom programmed by the operator to fit individual preferences. For information concerning custom programming available and programming instructions, refer to the vehicles owners manual.

Power Door Lock Deadbolt Operation (European)

Export vehicles may be equipped with the deadbolt feature, which includes a reversible deadbolt motor contained within each door latch assembly. Each deadbolt motor is wired to the driver door module (DDM) through 2 circuits; the deadbolt lock control circuit and the deadbolt unlock control circuit. To deadbolt a door, the body control module (BCM) locks the door by momentarily applying voltage to the door latch motor control circuit. The remote control door lock receiver (RCDLR) applies ground to the door latch enable control circuit to complete the circuit to the door latch motor. To complete the deadbolting, the DDM momentarily applies voltage to the deadbolt lock control circuit and ground to the deadbolt unlock control circuit. If the content theft feature is armed at the same time, the interior door lock switches will not operate the locks.

To undeadbolt the door, the DDM reverses the polarity, applying battery voltage to the deadbolt unlock control circuit, and ground to the deadbolt lock control circuit.

Power Door Lock Status Indicator

The driver door module (DDM) and front passenger door module (PDM) control the door lock status indicators for there respective doors. The DDM and PDM provide voltage to the indicators to illuminate when the lock system is in a virtual state of lock. The indicators only illuminate for approximately 5 seconds after lock switch activation or a door handle has been operated and the door control modules are in a virtual state of lock. When the door is open, the door lock status indicators cycle ON/OFF. The remote control door lock receiver (RCDLR) receives RFA transmissions and communicates with the door control modules for lock and unlock commands. The door lock status indicators are grounded at G201 for the driver door indicator and G202 for the passenger door indicator.