False Alarm

NOTE: Because many faults are intermittent, it can often be difficult to know which of the alarm loops is causing the false alarm.


Guard Alarm I:
Deactivate alarm.
Which alarm loop triggered the alarm is indicated as follows:
All indicator LEDs out: Ignition and/or panic function.
Indicator LED I lit: Door contact loop.
Indicator LED II lit: Hood (bonnet)/ trunk (boot).
Indicator LED III lit: Sensor loop.
The indicator LEDs will go out when the ignition is switched on or the alarm is reactivated. Then fault-trace in the alarm loop which triggered the false alarm.

Guard Alarm II:
Run alarm test of the last 10 alarms triggered using the testbox. See Test Guard Alarm II (only).

Sources of fault:
Short-circuit to ground.
Short-circuit to supply.
Fault-tracing starts with F1.

F1 Disconnect Alarm Loops
Deactivate alarm.





Ignition off.
Remove alarm control module (position 210/211).





Check that all wiring is in the right position.
Disconnect all alarm loops except ignition (15). This is done by disconnecting the leads from the relay center and insulating them with insulating tape or insulators.
Door contacts:
Yellow/white lead at position T.
Hood (bonnet) alarm loop:
Yellow/black lead at position FH.
Trunk (boot) alarm loop:
Blue/brown lead at position RH.





Sensor (Guard Alarm I and II only):
Disconnect the 4-pin connector from the sensor.





Check if false alarm persists
Ignition off.
Replace alarm control module (position 210/211).





Close all doors, hood (bonnet) and trunk (boot) lid.





Activate alarm.





If false alarm persists:
False alarm from ignition supply lead. Supply is reaching position 15 e.g. via an intermittent short-circuit to 12 V, e.g. due to worn leads, wet or dirty contacts in the connector or ignition.
Deal with fault.

If false alarm Stops:
Connect one alarm loop at a time until the faulty alarm loop is found (false alarm starts again).
Some common sources of faults in the different alarm loops are given below.

Fault in door contact loop may be because:
Door contacts are damaged, mechanically or electrically. One of the leads is trapped and is giving an intermittent ground connection.

Fault in hood (bonnet) and/or trunk (boot) loop may be because:
Hood (bonnet) and/or trunk (boot) contacts are damaged mechanically or electrically. One of the leads is trapped and is giving an intermittent ground connection.

Fault in sensor loop may be because:
Sensors are installed incorrectly or are poorly attached.

Other faults may be because:
Wiring connections are poorly made. Intermittent open-circuit in power supply or in grounding.

Other possible sources of alarms:
Animals in car, vibration while on board a ferry etc. or an open window is affecting the sensors.