No Alarm on Sensor

Sensors are connected toGuard Alarm I or Guard Alarm II wiring harness via the 4-pin connector. The alarm is triggered when the lead at position 3 receives a grounding signal. The equivalent position in the control module connector Guard Alarm I: 10-pin and Guard Alarm II: 5-pin is position 5.





NOTE: If more than one sensor is connected, check each sensor in turn.


Guard Alarm I:
A maximum of three alarms per sensor connected to alarm loop III can be triggered in every activation period. A maximum of 2 sensors can be connected. Check control module programing to see that FUNCTIONS 7 and 8 are not set to SIGNAL PATTERN 1 (no output signal). Check control module programing to see that FUNCTION 2 (SOFT automatic activation) is not set to 2 or 5 (sensor loop III disconnected). See Guard Alarm I, Description and Operation.


Sources of fault
Open-circuit in ground lead between alarm control module and connector.
Open-circuit in supply lead between alarm control module and connector.
Short-circuit to ground in supply lead between alarm control module and connector.
Open-circuit in signal lead between alarm control module and connector.
Fault in sensor or open-circuit in sensor leads.
Fault in alarm control module.

Fault-tracing starts with E1.

E1 Checking Ground Lead
Deactivate alarm.





Ignition off.





Remove the 4-pin connector from sensor.





Connect an ohmmeter between connector position 1 (ground) and ground. Ohmmeter should read approx. 0 ohm.




If reading is OK:
Check supply E2.

If reading is incorrect:
Check ground lead between sensor 4-pin connector position 1 and alarm control module connector:

Guard Alarm I: 10-pin connector position 1
Guard Alarm II: 5-pin connector position 3 (located on top of alarm control module) for open-circuit as per WA3 See Other Fault-Tracing Test in Basic Alarm. Deal with fault or replace lead.

E2 Checking Supply

Ignition off.
Connect a voltmeter to the 4-pin connector between position 2 and position 1 (ground). Voltmeter should read battery voltage.





If reading is OK:
Check signal lead from sensor E3.

If reading is incorrect:
Check supply lead between sensor 4-pin connector position 2 and alarm control module connector:

Guard Alarm I: 10-pin connector position 4
Guard Alarm II: 5-pin connector position 4 (located on top of alarm control module) for open-circuit as per WA3 and short-circuit to ground as per WA4 See Other Fault-Tracing in Basic Alarm. Deal with fault or replace lead.

E3 Checking Signal Lead From Sensor

Ignition off.





Activate alarm.





Wait at least 10 seconds.








Bridge the 4-pin connector between position 3 and position 1 (ground).
The alarm should be triggered.





If alarm is triggered:
Try another sensor.

If alarm is not triggered:
Check signal lead from connector to alarm control module E4.

Guard Alarm I window sensor:
Try to change programing of control module FUNCTION 1 to a higher sensitivity (VALUE 1 or 2).


E4 Checking Signal Lead From Connector To Alarm Control Module

Ignition off.





Remove connector from alarm control module:
Guard Alarm I: 10-pin connector
Guard Alarm II: 5-pin connector
Connect an ohmmeter between 4-pin connector position 3 and alarm control module connector position 5.





NOTE: Illustration shows 5-pin connector to Guard Alarm II.
Ohmmeter should read approx. 0 ohm.


If reading is OK:
Try another alarm control module after Fault-Tracing in Alarm Wiring Harness here in Guard Alarm I or II only.

Guard Alarm II:
Run control module self-test in Guard Alarm II only before replacing control module.

If reading is incorrect:
Check lead between 4-pin connector position 3 and alarm control module connector position 5 for open-circuit as per WA3 See Other Fault-Tracing Test in Basic Alarm. Deal with fault or replace lead.