Door Lock System Components
The power door lock system consists of the following components:
| • | Driver door lock switch -- Uses a single signal wire for both lock
and unlock switch activations |
| • | Front passenger door lock switch -- Uses a single signal wire for
both lock and unlock switch activations |
| • | BCM -- Class 2 module which requires programming when replaced |
| • | Reversible door lock actuators in each of the doors |
| • | BCM PWR 15A fuse -- Located in the BCM fuse panel, supplies power
for the door lock system |
Door Lock System Controls
The power door lock system can be controlled by any of the following:
| • | Power door lock switch activation |
| • | Keyless entry lock or unlock command, if equipped |
| • | Delayed locking command |
| • | Automatic door lock command |
| • | Lockout prevention command |
Door Lock and Unlock Operation
The BCM PWR fuse supplies battery positive voltage to the BCM for the door lock
system.
The BCM supplies and monitors a reference voltage to the door lock switch through
the door lock switch lock/unlock signal circuit. The door lock switch also receives
a constant ground source. If a door lock switch is placed in the lock position, the
reference voltage is taken directly to ground and the BCM senses 0.0 volts
on the signal circuit. If a door lock switch is placed in the unlock position, the
reference voltage is taken to ground through a 15k ohm resister that is internal
to the door lock switches and senses approximately 2.9 volts on the signal
circuit. This is how the BCM determines what portion of the door lock switch was
activated.
The BCM, upon receipt of a door lock switch lock or unlock signal, will switch
the appropriate door lock actuator control circuits to battery positive voltage.
The opposing side of the door lock actuators are connected to ground internally within
the BCM through the other door lock actuator control circuit and the doors will lock
or unlock appropriately.
Vehicles without keyless entry have two internal drivers in the BCM to control
the door lock actuators. All door lock and all door unlock. Vehicles equipped with
keyless entry have three internal drivers in the BCM. Driver door unlock, passenger
door unlock and all door lock. This is done to isolate the driver door lock actuator
so it can be unlocked by itself using the keyless entry transmitter.
Automatic Door Lock Operation
This BCM controlled feature can be personalized to driver preference. Refer
to
Power Door Systems Connector End Views
Personalization Description and Operation
in Personalization.
The BCM will automatically lock the vehicle doors if the following conditions
exist:
| • | All vehicles doors are closed. |
| • | The ignition is in the ON position. |
| • | The vehicle is shifted out of PARK. |
The BCM will then unlock the doors when the ignition is placed in the OFF position.
Delayed Locking Operation
With any door open and a door lock switch is activated in the lock position,
the BCM will give three audible chimes. When the door is closed, the BCM will cycle
the internal door lock relay to lock the doors after approximately five seconds.
This feature can be overridden by activating the door lock switch a second time and
the doors will lock even with a door open.
Lockout Prevention Operation
The BCM will lock all doors and unlock the driver door with a door lock switch
lock activation if a vehicle door is open and the ignition key is fully inserted
in the ignition. The lockout prevention feature can be overridden if a lock command
is received from the keyless entry system.
Unlock After Air Bag Deployment
This feature will unlock all of the vehicle doors 15 seconds after an
air bag deployment.
