Basic Alarm System

All inputs and outputs are protected against 12 V and grounding.
Check the following before the control module is exchanged:

Check the connections
- Ignition off.




- Disconnect the alarm control module (item C/F).

Check that item 31 is connected to ground




- Ignition off.
- Connect an ohmmeter between ground and the alarm relay base item 31. The ohmmeter should show approx. 0 ohms.

If the reading is correct:
- Proceed to item 30 check.

If the value deviates:
Item 31 is not grounded.
- Check connections. Refer to Checking Leads. Checking Leads and Connection
Rectify the fault or renew the lead.

Check that item 30 is connected to battery voltage.




- Ignition off.
- Connect a voltmeter between ground and the alarm relay base item 30 (base C). The voltmeter should show battery voltage.

If the reading is correct:
- Proceed to next measurement below.

If the reading deviates:
Voltage is missing at item 30.
- Check connections. Refer to Fault Alarm Wiring. Checking Leads and Connection

Rectify the fault or renew the lead.

Check that item 50F and item H are not shorted to ground.



- Ignition off.

Measurement A:
- First connect an ohmmeter between ground and the alarm relay base item 50F.
The ohmmeter should show approx. 1 ohm: this is correct and not a sign of shorting.

Measurement B:
- Then connect an ohmmeter between ground and the alarm relay base item H.
The ohmmeter should show approx. 1 ohm: this is correct and not a sign of shorting.

If readings A and B are both correct:
- Proceed to Measurement C.

If there is a deviation:

Measurement A:
There is a short to ground in the lead between item 50F and the starter motor.

Measurement B:
There is a short to ground in the lead between item H and the horn.
- Check connections. Refer to Fault Alarm Wiring. Checking Leads and Connection

Rectify the fault or renew the lead.

Measurement C:




- First connect an ohmmeter between ground and the alarm relay base item L. The ohmmeter should show approx 1 ohm: this is correct and not a sign of shorting.

Measurement D:
- Then connect an ohmmeter between ground and the alarm relay base item R. The ohmmeter should read approx. 1 ohm: this is correct and not a sign of shorting.

If readings C and D are in order:
- Check the connection. Refer to Fault Alarm Wiring. Checking Leads and Connection

Renew the control module.

If the readings deviate:
Measurement C:
There is a short to ground in the lead between item L and the left turn signal.

Measurement D:
There is a short to ground in the lead between item R and the right turn signal.
- Check the connections.
Rectify the fault or renew the lead.