Glass breakage sensor

Symptom: Grass breakage sensor does not trip the alarm.

Glass breakage sensor

Fault symptom

Grass breakage sensor does not trip the alarm.

Diagnostic procedure

1 Check the operation of the glass breakage sensor

-	Connect the ISAT scan tool.

-	Select "READ VALUES".

-	Select "GLASS BREAK SENSOR".

-	Jingle a bunch of keys or the like near the sensor.

The ISAT scan tool display should show a reading of between 10 and 255.

Is ISAT indicating the correct value?

yes

Continue with point 6.

no

Continue with point 2.

2 Check the operation of the glass breakage sensor

-	Disconnect the glass breakage sensor by unplugging the 4-pin connector.

-	Select "READ VALUES".

-	Select "GLASS BREAK SENSOR".

If the connector remains open, the ISAT scan tool display should show "0". Connect a jumper lead between pins 1 and 2 of the connector. The scan tool display should now show a reading of 255.

Is ISAT indicating the correct value?

yes

Change the glass breakage sensor.

no

Continue with point 3.

3 Check the operation of the electronic control module

-	Unplug connector H10-4.

-	Select "READ VALUES".

-	With the connector open, the ISAT scan tool display should show "0". With a jumper lead connected between pins 2 and 3 of connector H10-4, the scan tool display should show a reading of 255.

Is ISAT indicating the correct value?

yes

Continue with point 5.

no

Continue with point 4.

4 Check the wiring connected to the electronic control module

Conduct a continuity test on the cable assembly between

-	connector H10-4, pin 2 and the control module, pin 7.

-	connector H10-4, pin 3 and the control module, pin 5. The resistance should be < 1 ohm.

Is the resistance correct?

yes

Continue with point 6.

no

Repair or replace the wiring harness.

5 Check the wiring connected to the glass breakage sensor

Conduct a continuity test on the cable assembly between

-	connector H10-4 (pin 2) and the glass breakage sensor (pin 1).

-	connector H10-4 (pin 3) and the glass breakage sensor (pin 2). The resistance should be < 1 ohm.

Is the resistance correct?

yes

Carry out a visual inspection of the sensor and connector.

no

Repair or replace the wiring harness. If nothing can be found that can be corrected, change the glass breakage sensor.

6 Final check

-	Disconnect the ISAT scan tool.

-	Close all doors.

-	Arm the alarm and wait until the LED flashes at the rate of 1 flash every 2 seconds.

-	Jingle a bunch of keys close to the sensor.

Does the alarm go off?

yes

The remedial measures taken were correct or the fault is of intermittent nature.

no

See "Before replacing a control module".