Door Locks: Description and Operation

CIRCUIT OPERATION

When a Door Lock Switch is activated in the Power Door Lock System, both of the doors will lock or unlock in unison. Each lock can also be operated manually from the locking post. The locks are operated by reversible motors that receive voltage from two relays in the Door Lock Relay Assembly. These relays operate to activate the motors by applying a voltage to one of the terminals and a ground to the other terminal.

When either Door Lock Switch is moved to the LOCK position, it completes the circuit to the coil of the Door Lock Relay Assembly and the lock relay is energized. The contacts for the lock relay close and supply battery voltage to the Door Lock Motors through the GRY (295) wires.

The Door Lock Motors are grounded through the TAN (294) wires and the contacts of the Unlock Relay to G210 or G211. The motor in each door operates that door lock. When the Door Lock Switch is released, the Lock Relay contacts return to ground and the motors turn off.

A similar action occurs with the Unlock Relay when it is energized by either of the Door Lock Switches closing to the UNLOCK position. Now the TAN wires to the motors carry battery voltage and the GRY wires are grounded. The polarity of the voltage to the motors is 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 breakers close automatically when voltage is removed.