Power Locks: Description and Operation

CIRCUIT OPERATION

The Automatic Door Lock feature is controlled by the Chime Module, The Chime Module will send a 400 ms battery voltage signal to the coil of the Door Lock Relay once per Ignition cycle when two conditions are present.

AUTOMATIC TRANSAXLE - The Automatic Door Lock Signal is produced by the Chime Module when all doors are closed and the Transaxle Position Switch is moved out of "PARK" or "NEUTRAL."

WITHOUT KEY LESS ENTRY
When a Door Lock Switch is activated in the Power Door Locks System, all doors lock or unlock in unison. Each lock can also be operated manually from the locking knob. The locks are operated by reversible motors that receive voltage from two relays in the Power Door Lock Relay. These relays operate to turn the motors on by applying a voltage to one of the terminals and a ground to the other terminal. To reverse the motors, the polarity to the terminals must be reversed.

When either Door Lock Switch is moved to the "LOCK" position, it completes a circuit to the coil of the Power Door Lock Relay. The Power Door Lock Relay is energized. Its contact for the Lock Relay closes and is connected to battery voltage through CKT 60, which is the voltage feed for driving the motors.

Voltage is then applied to CKT 295 and to the Door Lock Motors, which are grounded by CKT 294 from the other terminal of the motor through the contact for the Unlock Relay. The motor in each door runs to operate the door lock. When the Door Lock Switch is released, the Lock Relay contact closes to ground again and the motors turn off.

A similar action occurs with the Power Door Lock Relay when it is energized by either of the Door Lock Switches closing to the "UNLOCK" position. Now CKT 294 to the motors carries battery voltage and CKT 295 is grounded. The polarity of the voltage to the motors has reversed. The motors run in the opposite direction to unlock the doors.

The Door Lock Switches are usually closed for just a moment. If they are held closed, a circuit breaker in each motor will open to protect against damage. The circuit breaker resets only after voltage is removed from the motor.

WITH KEYLESS ENTRY
All Door Locks operate the same as without Keyless Entry except the LH Door Lock. When either Door Lock Switch is moved to the "LOCK" position, the Power Door Lock Relay is energized and voltage is applied to CKT 295 and to the Door Lock Motors. The LH Front Door Motor is grounded through the Keyless Entry Module terminal "B". The other Door Lock Motors are grounded through the normally open contacts of the Unlock Relay. When either Door Lock Switch is moved to the "UNLOCK" position, voltage is applied to terminal "G" of the Keyless Entry Module. This is the Unlock Enable signal that tells the Keyless Entry Module to energize terminal "B", which then applies voltage to CKT 294 and to the LH Front Door Lock Motor. The LH Front Door Lock Motor is then grounded through the normally open Lock Relay contacts of the Power Door Lock Relay.