Door Lock System Components
The power door lock system consists of the following components:
|     •  | Rear door lock switch (utilities only) | 
 
|     •  | Driver door unlock relay (uplevel vehicles) | 
 
|     •  | Body Control Module (BCM) | 
 
|     •  | Reversible door lock actuators in each of the doors | 
 
|     •  | MIR/LOCK 3A fuse (switch supply voltage) | 
 
|     •  | DR LOCK 20A fuse (relay supply voltage) | 
 
|     •  | UNLOCK 15A fuse (unlock supply voltage) | 
 
|     •  | LOCK 15A fuse (lock supply voltage) | 
 
|     •  | UNLOCK JMPR (base vehicles) | 
 
Door Lock System Controls
The power door lock system can be controlled by any of the following:
|     •  | A power door lock or unlock switch activation | 
 
|     •  | A keyless entry transmission (uplevel vehicles) | 
 
|     •  | An automatic door lock function | 
 
|     •  | A delay lock function (utilities) | 
 
Driver and Passenger Door Lock Operation (Base Vehicles)
When any of the door lock switches are placed in the lock position,  voltage
is applied to the door lock control circuit and the lock relay winding.   Since the
other side of the lock relay winding is connected to ground,   the relay is energized.
This causes the contacts to close and complete   the path from the DR LOCK fuse through
the battery voltage circuit.  Voltage is then applied through the LOCK fuse to the
lock side of the  door lock actuators. Since the other side of the all the door lock
actuators  are connected to the normally closed contacts of the unlock relay to  ground
, the doors lock.
The lock function can also be accomplished by the BCM supplying voltage  to
the door lock control circuit during a delay lock function (utilities only).
Driver and Passenger Door Lock Operation (Uplevel Vehicles)
When any of the door lock switches are placed in the lock position,  voltage
is applied to the door lock control circuit and the lock relay winding.   Since the
other side of the lock relay winding is connected to ground,   the relay is energized.
This causes the contacts to close and complete   the path from the DR LOCK fuse through
the battery voltage circuit.  Voltage is then applied through the LOCK fuse to the
lock side of the  door lock actuators. Since the other side of the passenger door
lock  actuator(s) are connected to the normally closed contacts of the unlock  relay
to ground and the driver door lock actuator is connected to the  normally closed contacts
of the driver door unlock relay to ground,  the doors lock.
The lock function can also be accomplished by the BCM supplying voltage  to
the door lock control circuit by any of the following:
|     •  | A keyless entry lock transmission | 
 
|     •  | An automatic door lock function (if programmed) | 
 
|     •  | A delay lock function (utilities only) | 
 
Driver and Passenger Door Unlock Operation (Base Vehicles)
When any of the door lock switches are placed in the unlock position,  voltage
is applied to the door unlock signal circuit and the BCM. When the BCM senses the
voltage signal, it grounds the door unlock control circuit   and the unlock relay
winding. Since the other side of the unlock relay   winding is connected to battery
voltage, the relay is energized. This  causes the contacts to close and complete the
path from the DR LOCK  fuse through the battery voltage circuit. Voltage is then applied
through  the UNLOCK fuse to the unlock side of the door lock actuators. Since  the
other side of the door lock actuators are connected  to the normally closed contacts
of the lock relay to ground, the doors  unlock.
Passenger Door Unlock Operation (Uplevel Vehicles)
When any of the door lock switches are placed in the unlock position,  voltage
is applied to the door unlock control circuit and the unlock relay   winding and the
BCM. Since the other side of the unlock relay winding is connected   to ground, the
relay is energized. This causes the contacts to close   and complete the path from
the DR LOCK fuse through the battery voltage   circuit. Voltage is then applied through
the UNLOCK fuse to the unlock   side of the door lock actuators. Since the other side
of the door lock   actuators are connected to the normally closed contacts of the
lock  relay to ground, the doors unlock.
The unlock function can also be accomplished by the BCM supplying
voltage  to the door lock control circuit during any of the following:
|     •  | A keyless entry unlock transmission | 
 
|     •  | An automatic door unlock function (if programmed) | 
 
Driver Door Unlock Operation (Uplevel Vehicles)
The driver door unlock control circuit uses a dedicated driver door  unlock
relay. This is done so that the driver door may be unlocked by itself   using a keyless
entry unlock transmission or with an automatic door  unlock function (if programmed).
The driver door unlock relay differs  slightly from the unlock relay in that the primary
side of the relay  is connected to the DR LOCK fuse and the door unlock control circuit
 is pulled to ground by the BCM to energize the relay.
When any of the door lock switches are placed in the unlock position,  a voltage
is applied to the unlock relay and to the BCM. When the BCM senses   the voltage signal,
it grounds the driver door unlock control circuit.   Since the other side of the driver
door unlock relay winding is connected   to the DR LOCK fuse through the battery voltage
circuit, the relay is   energized. This causes the contacts to close and complete
the path from   the DR LOCK fuse through the battery voltage circuit. Voltage is then
  applied to the unlock side of the driver door lock actuator. Since the   other side
of the driver door lock actuator is connected to the normally   closed contacts of
the lock relay to ground, the driver door unlocks.
The unlock function can also be accomplished by the BCM supplying voltage  to
the door lock control circuit during any of the following:
|     •  | A keyless entry unlock transmission | 
 
|     •  | An automatic door unlock function (if programmed) | 
 
Delay Locking (Utility Vehicles)
This feature allows the operator to lock all the doors from the rear  lock switch.
The rear cargo doors have contact plates that complete the power   door lock and unlock
fuse supply circuits (among others) when the cargo   doors are closed, and interrupt
these circuits when the cargo doors  are open. When a lock function occurs and the
BCM senses an active state   on the lift gate ajar switch signal circuit (door open),
the driver  and passengers doors will lock as described, and the BCM continues  to
monitor the lift gate ajar switch signal circuit . When the BCM  senses an inactive
state (door closed), the BCM will cycle the door  lock relay again after approximately
5 seconds to perform another lock  function, thus locking the cargo door.
Lockout Prevention
This feature prevents the locking of the driver door if the ignition  key is
left in the ignition lock cylinder. If a lock function occurs from   any door lock
switch and the BCM senses an active state on either the   left front door latch signal,
secondary door latch switch signal and/or   the lift gate ajar switch signal circuits
and the key in ignition switch   signal circuit is in the yes state, the BCM will
cycle the door lock   relay to lock the doors and then cycle the driver door unlock
relay  to unlock the driver door.
Programmable Automatic Door Locks
The automatic door lock feature can be programmed to control the door  lock
system. The automatic door lock feature is factory programmed to have  all doors lock
and unlock. For detailed instructions on programming the automatic  door locks, refer
to 
Vehicle Personalization 
 in Personalization.
When the automatic door lock feature is programmed to control the door  lock
system, the BCM will lock the vehicle doors if the following inputs are  true:
|     •  | Ignition 1 input is active. | 
 
|     •  | All door jamb switch inputs are inactive. | 
 
|     •  | Cargo door or lift gate/lift glass ajar inputs are inactive. | 
 
|     •  | Transmission is shifted out of park | 
 
This automatic door lock function will only occur once per ignition  cycle unless,
a door jamb switch input changes state to active and back to inactive.  Then the BCM
will lock all doors again.
Once the automatic door lock feature has locked the doors, the BCM will  then
unlock all the doors when the transmission is shifted into park.