Driver and Passenger Door Lock Operation

When any of the door lock switches is pressed to the lock position, the BCM door lock/unlock signal circuit changes from an idle voltage of 3.4 volts to 0.0 volts generating a lock command. The BCM then applies battery positive voltage to the Door Lock Relay, which in turn applies battery positive voltage to the Door Lock Actuator lock circuit of all the Door Lock Actuators. Since the Door Lock Actuator unlock circuits are held to ground through the resting Door Unlock Relay(s), the actuators execute the lock command, locking the doors.

The lock function can also be accomplished by the BCM having received a keyless entry door lock command, if the vehicle is equipped with keyless entry.