System Diagnosis

CIRCUIT OPERATION

Description

The Theft Deterrent System - when armed - flashes the exterior lamps and sounds the horns if theft is attempted. The system also interrupts the starter circuit so the car cannot be started once the alarm has been energized.

Warning Indicator

The "SECURITY SYSTEM" Warning Indicator in the INSTRUMENT PANEL goes on when one of the doors is opened. The Indicator flashes if the system has not been armed. If the system has been armed, the Indicator stays on steadily for three seconds after the last door is closed.

Current Flow

This system uses voltage through five fuses for proper operation. Voltage is applied at all times through IN-LINE FUSE A, IN-LINE FUSE B, the Ltr Fuse, and the Body Fuse. With the IGNITION SWITCH in "RUN," voltage is applied through the Ga-Trans Fuse to the THEFT DETERRENT CONTROLLER.

The "SECURITY SYSTEM" Warning Indicator lights when a ground is provided by the THEFT DETERRENT CONTROLLER. When the CONTROLLER senses no voltage from the Ga-Trans Fuse (IGNITION SWITCH "OFF") and any DOOR JAMB SWITCH is closed (door open), the Indicator flashes on and off to indicate an unarmed condition. When either DOOR LOCK SWITCH is pressed to "LOCK," the Indicator stays on constantly.

When all DOOR JAMB SWITCHES are open (all doors closed), the system is armed. The indicator stays on steadily for three seconds and goes out.

Before the doors are closed, the arming operation can be cancelled by pressing either DOOR LOCK SWITCH to "UNLOCK."

To disarm the system, one of the DOOR LOCK CYLINDER SWITCHES must be closed to ground by unlocking either door with a key. When either door is unlocked, the THEFT DETERRENT CONTROLLER detects a ground at terminal H and disarms the system.

When the system is armed, any one of the following three actions triggers the alarm by grounding the 263 Tamper Input circuit: 1) opening any door; 2) tampering with trunk lock cylinder (TRUNK LID TAMPER SWITCH); 3) tampering with either door lock cylinder.

When the 263 Tamper Input circuit is grounded through any of these actions, the CONTROLLER energizes the THEFT DETERRENT RELAY. With the RELAY contacts closed, voltage is applied through IN-LINE FUSE A to the horns and through IN-LINE FUSE B to the exterior lamps. The horns and lamps pulse 25 times per minute for three to seven minutes. The CONTROLLER also energizes the STARTER INTERRUPT RELAY and disables starter operation.