Locks: Description and Operation

Power Door Locks Circuit Description

When a power door lock switch is operated, both of the doors will lock or unlock. Each door lock can also be operated manually. The door locks operate by reversible motors that receive voltage from the DR LK circuit breaker. The power door lock switches turn the motors on by supplying battery voltage to one of the terminals and ground to the other terminal.

When either door lock switch moves to the LOCK position, it completes the circuit to the motors. Voltage is supplied to CKT 295 (GRY) and to the door lock motors, which are grounded by CKT 294 (TAN) from the other terminal of the motor through the UNLOCK switch contact and to the ground. The power door lock motor in each door runs to operate the door locks. When the power door lock switch is released, the circuit opens and the power lock motors turn off.

A similar action occurs with either of the power door lock switches closing to the UNLOCK position. Now CKT 249 (TAN) supply battery voltage to the power door lock motor and CKT 295 (GRY) are grounded. The polarity of the voltage to the power door lock motors has reversed. The power door lock motors run in the opposite direction to unlock the doors.

The power door lock switches are usually closed for just a moment. If the power door lock switches are held closed, a circuit breaker in each power door lock motor will open to protect against damage. The circuit breakers reset automatically when they cool off.