Power Locks: Description and Operation

The Power Door Locks are operated by reversible motors located in each front door, the side door and the RH rear door. Voltage to the door locks is supplied through the PWR ACC circuit breaker.

Moving either Door Lock Switch mounted in the front doors to LOCK supplies voltage to the lock coil of the Door Lock Relay. This energizes the lock coil in the relay and current flows directly to the Front Door Locks through the 295 (GRA) wires. Current for the Rear Door Lock and the Side Door Locks flows through the normally closed contacts of the Lock Delay Relay, then to the motors. Ground for the motors is provided through the 294 (TAN) wires and the normally closed contacts of the UNLOCK contacts in the Door Lock Relay.

Moving one of the Door Lock Switches to UNLOCK reverses the polarity of the system. Current flows through the energized UNLOCK contacts in the Door Lock Relay and ground is provided through the LOCK contacts in the Door Lock Relay.

If the side door is open, a ground signal from the Side Door Jamb Switch is sent to the Door Lock Delay Module. If the Door Lock Switch is moved to LOCK while the side door is open, the two front doors are locked and a LOCK signal is sent to the Door Lock Control Module at terminal C.

When the side door is closed the Door Jamb Switch opens, breaking the ground signal. This starts a five-second timer in the Module. After five seconds, voltage is supplied to the Delay Relay from terminal H of the Door Lock Delay Module. This energizes the Delay Relay sending voltage to the Side Door Lock Motor and the Rear Door Lock Motor.

Unlocking the doors resets the five-second timer in the Door Lock Control Module.