Universal Theft Deterrent (UTD)

CIRCUIT OPERATION
The Theft Deterrent System is designed to sound the horns and flash the exterior lights, when the system is armed and entry is gained forcibly through the doors. Alarms

Operation of the exterior lights and horns when activated, is controlled by the Theft Deterrent Module via the BCM and Horn Relay.

When the alarm is active the Theft Deterrent Module cycles the alarm system control driver (terminal F) on and off once per second. During this cycle, ground is applied through CKT 265 to the BCM and Horn Relay and then removed. This signals the BCM to ground CKT 911 at terminal 2A9 which in turn energizes the Park Light Redundant Relay and the Lo Beam Relay, causing their respective lights to flash. The same output from the Theft Deterrent Module grounds CKT 28 through the Diode Assembly which energizes the Horn Relay, causing the horns to sound.

The Diode Assembly is installed in the circuit to provide circuit isolation. If the Diode Assembly were to short some unusual symptoms might occur such as the headlights light when the horn is sounded.

Arming
Arming the Theft Deterrent System is a four step procedure. The arming sequence begins when the ignition is turned off. This removes battery voltage at module terminal K, the ignition 1 input. Step 2 occurs when a door is opened and ground is applied to module terminal J, the tamper input. The system is still not armed so grounding the tamper input at this time does not set off the alarms. The THEFT SYSTEM ARMED indicator flashes to alert the operator the system is not armed. Step 3 occurs when the doors are locked electrically, this applies battery voltage through CKT 195 to the module's terminal G, the system arm input. The THEFT SYSTEM ARMED indicator is on steady to indicate that the system is armed. The arming sequence is completed when all doors are closed, removing ground from the module's terminal 3, the tamper input. The system is now armed. The THEFT SYSTEM ARMED indicator will remain on for a few seconds.

Cancellation
The arming sequence can be canceled by unlocking the doors electrically prior to closing the door. When the doors are unlocked, voltage is momentarily applied through CKT 194 to the theft module's terminal M. This signals the module not to arm and the module will ignore the door being closed.

Disarming
When one of the front doors is unlocked with a key, the Front Door Lock Cylinder Switch closes. This grounds CKT 262 and the theft module's disarm input, terminal H. The system is now disarmed and no alarms will operate when a door is opened. Unlocking the trunk with a key closes the Trunk Lock Cylinder Switch, grounding CKT 260 and terminal 2B3 of the BCM, the trunk lock cylinder switch input. The BCM, receiving this ground input twice within 10 seconds, grounds terminal 3C13, the theft alarm disarm output. This grounds CKT 262 and terminal H of the Theft Deterrent Module, disarming the system.

Tampering
The alarms are set off when the theft module's tamper input, terminal J, is momentarily grounded after the system has been armed. This will occur when a door is opened causing a door ajar switch to ground CKT 263. THEFT SYSTEM ARMED Indicator

The THEFT SYSTEM ARMED indicator reminds the operator to arm the system by flashing and indicates that the system is armed when it stays on steady. The Theft Deterrent Module controls the indicator by grounding it through the indicator control driver at terminal D. The PASS-Key system also uses the THEFT SYSTEM ARMED indicator to inform the driver about its status.