Power Locks: Description and Operation

CIRCUIT DESCRIPTION

Battery voltage is applied at all times to the door lock relays and unlock relay. When locking the vehicle by using the door unlock switch in the left power window switch, the door unlock switch will provide a ground to the lock relay and the doors lock. When locking the doors by using the vehicle key or pushing down the lock knob, a signal will be sent to the body control module. The control module will then ground the relay according to the vehicle speed and the doors lock. The body control module also has an input from the ignition key switch. This input prevents the doors from accidentally being locked when exiting the vehicle with the ignition off and the key left in the ignition switch.

When you turn the driver's master switch assembly to the UNLOCK position, a path to ground is supplied to the unlock relay. Battery voltage is applied to the door lock actuators. The polarity of the voltage applied to the actuators is now reversed and the doors unlock.