GM Service Manual Online
For 1990-2009 cars only

Power Door Lock Components

The power door lock system consists of the following components:

    • Driver door lock switch
    • Passenger front door lock switch
    • Driver door switch assembly (DDSA)
    • Driver door module (DDM)
    • Passenger front door module (PDM)
    • LH rear door module (LRDM)
    • RH rear door module (RRDM)
    • Driver door lock actuator
    • Passenger front door lock actuator
    • LH rear door lock actuator
    • RH rear door lock actuator
    • Rear integration module (RIM)
    • Driver DR MOD fuse (10-amp)
    • PSGR DR MOD fuse (10-amp)
    • REAR DR MOD fuse (15-amp)
    • Class 2 serial data link

Door Lock System Controls

The power door lock system can be controlled by any of the following:

    • A power door lock switch activation
    • A remote keyless entry transmission
    • A driver door key cylinder unlock switch activation
    • An automatic door lock function

Power Door Lock Operation

Each door lock actuator is powered and controlled by the door module mounted in the individual door, but the rear integration module (RIM), which is the master control for the door lock system, determines when the lock functions are permitted. The RIM receives and examines lock function requests from the individual door modules, or from the remote function actuator (RFA) via the class 2 serial data circuit. The RIM also examines the transmission shift selector position and the ignition switch position information available over the class 2 serial data circuits. If the RIM determines that all conditions are correct for a lock or unlock function to be permitted, it sends a class 2 message back to the individual door modules commanding them to perform the lock or unlock function requested.

Door Modules Power and Ground

Each door module has a separate battery voltage circuit fed by the rear fuse block. Each door module is separately grounded through one or more circuits connected to a ground stake. These voltage and ground circuits are in the C3 harness connector of each door module and are used for power door lock operations, as well as to power up the door modules. These circuits are also used for power outside rearview mirror operations and for some power window functions, which are covered in the applicable description and operations section.

The DDM battery voltage circuit is fed by the DRIVER DR MOD 10-amp fuse.

The PDM battery voltage circuit is fed by the PSGR DR MOD 10-amp fuse.

The LRDM and RRDM also have separate battery voltage circuits, but they are both fed by the REAR DR MOD 15-amp fuse.

These circuits must not be confused with the voltage and ground circuits of door modules harness connector C1, which are used exclusively to drive the power window motors.

Power Door Lock Switches

The rear passenger doors are not provided with power door lock switches.

The front passenger door lock switch is wired to the front passenger door module. The lock switch is supplied battery voltage and ground by the front passenger door module. There are 2 circuits for voltage, one for a lock signal, and one for an unlock signal. The module supplies ground to the switch via a third circuit. When the switch is activated for a lock or unlock function, the normally open switch contacts for that function are closed and voltage flows through the switch, providing the module with the appropriate signal input.

The driver door lock switch is similar to the front passenger door lock switch, but it is wired to the driver door switch assembly (DDSA), and, for a ground circuit, to the driver door module. It also works the same way as the front passenger door lock switch works, but the switch activations are detected and processed by the DDSA and less voltage is required. The DDSA has 2 circuits that each supply 5-volts to the driver door lock switch, one for a lock signal, and one for an unlock signal. The driver door lock switch ground circuit is provided by the driver door module. When the door lock switch is activated, the normally open switch contacts for that function are closed, the voltage flows through the switch and is detected by the DDSA. The DDSA then relays the switch information to the driver door module via the class 2 serial data circuit.

Power Door Lock Motors

A power door lock motor is contained within each door lock actuator. Each door module supplies battery voltage and ground, through the door lock actuator motor control circuits to its associated door lock actuator motor. The power door lock motors are reversible. The function performed by the lock motor, lock or unlock, depends on which motor control circuit the voltage is applied to, and which motor control circuit the ground is applied to. To perform a lock function, the module momentarily applies voltage to the door lock motor lock control circuit, and ground to the door lock motor unlock control circuit. To perform a unlock function, the door module reverses the polarity and momentarily applies voltage to the door lock motor unlock control circuit, and ground to the door lock motor lock control circuit.

Power Door Lock Deadbolt Motors (Export)

Export vehicles may have the deadbolt feature, which includes a reversible deadbolt motor contained within each door lock actuator. Each deadbolt motor is wired to the associated door module through two circuits; the deadbolt motor control circuit and the door lock motor unlock control circuit, which it shares with the associated door lock motor. The deadbolt motor functions much the same as the lock motor. To deadbolt a door, the door module first locks the door by momentarily applying battery voltage to the door lock motor lock control circuit, and ground to the door lock motor unlock control circuit. To complete the deadbolting, the door module then momentarily applies battery voltage to the deadbolt motor control circuit, and, again, ground to the door lock motor unlock control circuit. Once the door is deadbolted, the mechanical lock/unlock linkage within the door lock actuator is physically disconnected so that the door can not be manually unlocked. If the content theft feature is armed at the same time, it also will not be possible to use the interior door lock switches to operate the locks.

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

Automatic Door Locks

The automatic door lock system provides for the locking or unlocking of one, or, all of the doors when shifting the transmission. When the vehicle doors are closed, the ignition is turned to ON, and the transmission is shifted out of PARK, all the doors will lock. When the vehicle is stopped and the transmission is shifted into PARK, one, or, all of the doors will unlock. For vehicles equipped with a manual transmission, all doors will lock when the vehicle exceeds 13 km/h (8 mph).

Operation of the automatic door lock system also depends upon door status information gathered by the associated door module, and examined by the rear integration module (RIM). The system will not operate properly if the RIM, which is the door lock master, detects that a vehicle door is open. Each door lock actuator contains a door open switch. Each door open switch receives battery voltage and ground from the associated door module. When a door is open, the switch closes, battery voltage flows through the switch, and the door module interprets the flow of voltage as a door open input. The door module then sends this information out over the class 2 serial data circuit, where it is detected by the RIM, as well as other concerned modules. If the RIM determines that one of the vehicle doors is open, automatic door locking will not be permitted.

The signals supplied by the door open switches are also used by the lighting system in order to determine when to turn the vehicle courtesy lamps On or Off. For more information concerning courtesy lamps and the door open switches, refer to Interior Lighting Systems Description and Operation .

It should further be noted that, while each door open switch shares its ground circuit with another switch in the door lock actuator, the door ajar indicator switch, the two switches must not be confused when service is required. Unlike the door open switch, the door ajar indicator switch has no affect on door locking. For more information concerning door ajar indicators and the door ajar indicator switches, refer to Indicator/Warning Message Description and Operation .

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 vehicles owners manual.

Anti-Lockout Feature

Leaving the key in the ignition with any door open will disable the use of the power door locks and the remote keyless entry (RKE) lock function.

The anti-lockout feature can be overridden by holding the lock switch in the LOCK position for more than 3 seconds.

Power Door Lock Deadbolt Operation (Export)

To operate the deadbolt feature, the door key is turned to the lock position, which causes all doors to lock immediately. If the door key is then held to the Lock position for 3 seconds or longer, or, turned to the Lock position twice within 3 seconds, the DDM interprets the key cylinder lock switch input as a deadbolt request. The DDM then sends a class 2 message to the RIM indicating the request. If the RIM determines that the deadbolt request is a valid request and conditions are correct for the door modules to perform the deadbolt function, it sends a class 2 message to all of the door modules to deadbolt all doors. When the doors are deadbolted, all doors are locked and the mechanical lock/unlock linkage within each door lock actuator is physically disconnected so that no door can be manually unlocked. If the content theft deterrent has also been armed, it also will not be possible to unlock the doors using the interior door lock switches.

To undeadbolt the doors with the driver door key, the key cylinder unlock switch is used. The key cylinder unlock switch input is interpreted as an undeadbolt request because the vehicles content options are configured for export. The normally open key cylinder unlock switch contacts receive battery voltage, via the key cylinder unlock signal circuit, and ground via the ground circuit, from the DDM, just as they do on a vehicle with the central door unlock feature. When the driver door lock cylinder is turned to unlock, the switch contacts close and the DDM detects the flow of voltage as an input. The DDM then sends a class 2 message to the RIM, indicating the switch request. The RIM interprets this key cylinder unlock switch request as an undeadbolt request. If all conditions are correct, the RIM sends a message back to all door modules to undeadbolt. The driver door will be both unlocked and undeadbolted, while the passenger doors will be only undeadbolted. The passenger doors can then be unlocked manually, or, by using either the interior lock switch or the remote transmitter.

By performing the following actions, the doors can also be locked and deadbolted, or unlocked and undeadbolted using the remote transmitter:

    • Press the remote transmitter lock button once to lock all doors, then press a second time within 3 seconds to deadbolt all doors.
    • Press the remote transmitter unlock button once to undeadbolt and unlock the driver door and undeadbolt all passenger doors, then press a second time within 3 seconds to unlock all passenger doors