Power Locks: Description and Operation

LOCKING
When a door lock switch is in the LOCK position, voltage from Fuse C3 is applied to the Door Lock Relay's lock coil through CKT 440, the Door Lock Switch lock contacts, CKT 780, the contacts of the Lockout Inhibit Relay and CKT 195. With voltage applied to the Door Lock Relay's lock coil, the relay energizes, allowing voltage from Circuit Breaker 3 to be applied to the Door Lock Motors through the closed relay contacts and CKT 295. The Door Lock Motors lock the doors because they are grounded. The RH front and rear (on four door models) Door Lock Motors are grounded at ground G401 through CKT 294, the unlock relay contacts and CKT 1250. The LH Front Door lock Motor is grounded at G401 through CKT 694, the Keyless Entry Module and CKT 1250.

LOCKOUT INHIBIT
The lockout inhibit feature disables the lock circuit when the key is left in the ignition (in ACCY, LOCK or OFF) and the driver's door is open or ajar.

Battery voltage is applied at all times to the coil of the Lockout Inhibit Relay through Fuse C5 and CKT 340. When the key is left in the ignition in the ACCY, LOCK or OFF position and the driver's door is opened the Ignition Key Warning and LH Front Door Ajar Switches close. This grounds the Lockout Inhibit Relay Coil and the relay energizes opening the contacts. The lock circuit path to the Door Lock Relay between CKTs 780 and 195 is opened at the relay contacts.

UNLOCKING
The unlocking operation is similar to the locking operation except that the polarity of the voltage applied to the Door Lock Motors is reversed. This causes the motors to run in the opposite direction, unlocking the doors.

When a Front Door Lock Switch is moved to the UNLOCK position, voltage is applied to the Door Lock Relay's unlock coil through fuse C3, CKT 440, the Door Lock Switch unlock contacts and CKT 194. The unlock relay contacts close and voltage is applied to the RH Front and Rear (on four door models) Door Lock Motors through CKT 294.

Voltage to unlock the LH Front Door Lock Motor is applied through a relay internal the Keyless Entry Module. When a Door Lock Switch is moved to the UNLOCK position, voltage is applied to the Keyless Entry Module at terminal C2 (the unlock enable input) through CKT 194. In response to this input the Keyless Entry Module switches on an internal relay which connects module terminals D1 and C16. Voltage is now applied to the LH Front Door Lock Motor through circuit breaker 3, CKT 742, the Keyless Entry Module and CKT 694.

All of the Door Lock Motors run because they are grounded through CKT 295, the lock relay contacts of the door lock relay and CKT 1250 at ground G401