Circuit Operation

The Anti-theft System consists of the following components:
Anti-theft and Keyless Entry control unit
Left and right door switches
Left front, right front, and tailgate door key detect and tamper switches
Tailgate switch
Engine hood switch
Door lock actuators
Left and right front door lock switches
Lighting relay
Starter relay
Headlights
"ANTI-THEFT" indicator light
Anti-theft horn

The arming sequence is initiated with the starter switch in the LOCK position and all doors closed. This results in all theft related switches to be open to ground. The "ANTI-THEFT" indicator then flashes for about 30 seconds or until the arming sequence is completed. When the driver's door is locked using the door key, the door lock actuator internal switch will open, removing the ground signal from the anti-theft and keyless entry control unit input. Now all inputs to the anti-theft and keyless entry control unit are open to ground and the "ANTI-THEFT" indicator stays lit for about 8 seconds. The anti-theft system is now armed. If any of the theft related switches are grounded, the theft alarm is activated. The anti-theft and keyless entry control unit does not allow the vehicle to be started by not applying ground to the starter relay. The anti-theft and keyless entry control unit pulses a ground signal to the lighting relay causing the headlights to flash. At the same time, the anti-theft and keyless entry control unit pulses a ground signal to the anti-theft horn, causing it to sound. The system alarm is cancelled when the anti-theft and keyless entry control unit sees battery voltage at its ignition input or a ground signal at its key detect input.