Fault-Tracing In Alarm

All Inputs And Outputs Are Short-Circuit Protected To 12 V And Ground.

First check that all leads are connected to the two relay plinths and to the 10-pin connector Guard Alarm I or 5-pin connector Guard Alarm II.

NOTE: Check fuses 2, 6 and 13 before starting fault-tracing.


Sources of fault
Open-circuit in ground lead to alarm relay plinth.
Open-circuit in supply to alarm relay plinth.
Short-circuit to ground in supply to alarm relay plinth.
Short-circuit to ground in position L, R, H or 50F in alarm relay plinth.

For Guard Alarm I:
Short-circuit to supply in accessory wiring leads.
Short-circuit to ground in accessory wiring leads.
Short-circuit between accessory wiring leads.

For Guard Alarm II:
Short-circuit to supply in accessory wiring ground leads.

Fault-tracing starts with U1.

U1 Checking Ground Lead

Deactivate alarm.





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





Connect an ohmmeter between alarm relay plinth position 31 (ground) and ground. Ohmmeter should read approx. 0 ohm.





If reading is OK:
Check supply U2.

If reading is incorrect:
Check lead between alarm relay plinth position 31 (ground) and ground point 31/51 for open-circuit as per WA3 See Other Fault-Tracing Test in Basic Alarm. Deal with fault or replace lead.



U2 Checking Supply

Ignition off.
Connect a voltmeter to alarm relay plinth between position 30 (plinth 210) and position 31 (ground). Voltmeter should read battery voltage.





If reading is OK:
Check position H for short-circuit to ground U3.

If reading is incorrect:
Check supply lead between battery and alarm relay plinth position 30 (plinth 210) for open-circuit as per WA3 and short-circuit to ground as per WA4 See Other Fault-Tracing Test in Basic Alarm. Deal with fault or replace lead.


U3 Checking Position H For Short-Circuit To Ground

Ignition off.
Connect an ohmmeter to alarm relay plinth between position H and position 31 (ground). Ohmmeter should read approx. 1 ohm. This is correct and not a sign of a short-circuit.





If reading is OK:
Check position 5OF for short-circuit to ground U4.

If reading is incorrect:
Check lead between alarm relay plinth position H and horn position 1 for short-circuit to ground as per WA4 See Other Fault-Tracing Test in Basic Alarm. Deal with fault or replace lead.


U4 Checking Position 50F For Short-Circuit To Ground

Ignition off.
Connect an ohmmeter to alarm relay plinth between position 50F and position 31 (ground). Ohmmeter should read approx. 1 ohm. This is correct and not a sign of a short-circuit.





If reading is OK:
Check position L for short-circuit to ground U5.

If reading is incorrect:
Check lead between alarm relay plinth position 5OF and starter motor for short-circuit to ground as per WA4 See Other Fault-Tracing Test in Basic Alarm. Deal with fault or replace lead.


U5 Checking Position L For Short-Circuit To Ground

Ignition off.
Connect an ohmmeter to alarm relay plinth between position L and position 31 (ground). Ohmmeter should read approx. 1 ohm. This is correct and not a sign of a short-circuit.





If reading is OK:
Check position R for short-circuit to ground U6.

If reading is incorrect:
Check lead between alarm relay plinth position L and LH turn signal (indicator) for short-circuit to ground as per WA4 See Other Fault-Tracing Test in Basic Alarm. Deal with fault or replace lead.


U6 Checking Position R For Short-Circuit To Ground

Ignition off.
Connect an ohmmeter to alarm relay plinth between position R and position 31 (ground). Ohmmeter should read approx. 1 ohm. This is correct and not a sign of a short-circuit.





If reading is OK:
Basic alarm: Try another alarm control module.
Guard Alarm I: Check Guard Alarm I accessory wiring for short-circuit to supply U7.
Guard Alarm II: Check Guard Alarm II accessory wiring for short-circuit to supply U11.

If reading is incorrect:
Check lead between alarm relay plinth position R and RH turn signal (indicator) for short-circuit to ground as per WA4 See Other Fault-Tracing Test in Basic Alarm. Deal with fault or replace lead.


U7 Checking Guard Alarm I Accessory Wiring For Short-Circuit To Supply

Ignition off.
Replace alarm control module.
Disconnect 10-pin connector from alarm control module.





Test A:
Connect a voltmeter between 10-pin connector position K1 and ground.
Voltmeter should not read battery voltage.





Test B:
Connect a voltmeter between 10-pin connector position K2 and ground.
Voltmeter should not read battery voltage

Test C:
Connect a voltmeter between 10-pin connector position K3 and ground.
Voltmeter should not read battery voltage.

If readings are OK:
Check Guard Alarm I accessory wiring for short-circuit to supply U8.

If any reading is incorrect:
Check appropriate lead between 10-pin connector and status panel for short-circuit to supply as per WA5 See Other Fault-Tracing Test in Basic Alarm. Deal with fault or replace lead.

U8 Checking Guard Alarm I Accessory Wiring For Short-Circuit To Supply

Ignition on.





Teat A:
Connect a voltmeter between 10-pin connector position K1 and ground.
Voltmeter should not read battery voltage.





Test B:
Connect a voltmeter between 10-pin connector position K2 and ground.
Voltmeter should not read battery voltage.


Test C:
Connect a voltmeter between 10-pin connector position K3 and ground.
Voltmeter should not read battery voltage.

If readings are OK:
Check Guard Alarm I accessory wiring for signal lead resistance to ground U9.

If any reading is incorrect:
Check appropriate lead between 10-pin connector and status panel for short-circuit to supply as per WA5 See Other Fault-Tracing Test in Basic Alarm. Deal with fault or replace lead.



U9 Checking Guard Alarm I Accessory Wiring F Signal Lead Resistance To Ground

Ignition off.





Test A:
Connect an ohmmeter between 10-pin connector position K2 and ground.
Ohmmeter should read infinite resistance.

Test B:
Connect an ohmmeter between 10-pin connector position K3 and ground.
Ohmmeter should read infinite resistance.




Test C:
Connect an ohmmeter between 10-pin connector position K4 and ground.
Ohmmeter should read infinite resistance.

If readings are OK:
Check Guard Alarm I accessory wiring for short-circuit between signal leads U10

If any reading is incorrect:
Check appropriate lead between 10-pin connector and status panel for short-circuit to ground as per WA4 See Other Fault-Tracing Test in Basic Alarm. Deal with fault or replace lead.



U10 Checking Guard Alarm I Accessory Wiring For Short-Circuit Between Signal Leads

Ignition off.





Test A:
Connect an ohmmeter between 10-pin connector position K1 and position K2. Ohmmeter should read infinite resistance.





Test B:
Connect an ohmmeter between 10-pin connector position K1 and position K3. Ohmmeter should read infinite resistance.


Test C:
Connect an ohmmeter between 10-pin connector position K4 and position K2. Ohmmeter should read infinite resistance.

Test D:
Connect an ohmmeter between 10-pin connector position K4 and position K3. Ohmmeter should read infinite resistance.


If readings are OK:
Try another alarm control module.
Reprogram remote control

If any reading is incorrect:
Check appropriate lead between 10-pin connector and status panel for short-circuit to ground as per WA4 and short-circuit to supply as per WA5 See Other Fault-Tracing Test in Basic Alarm. Deal with fault or replace lead.



U11 Checking Guard Alarm II Accessory Wiring For Short-Circuit To Supply





Ignition off.
Replace alarm control module (position 210/211).
Remove 5-pin connector from alarm control module.





Test A:
Connect a voltmeter between 5-pin connector position 2 and ground.
Voltmeter should read 0 V.

Test B:
Now connect voltmeter between 5-pin connector position 3 and ground.
Voltmeter should read 0 V.





If readings are OK:
Try another alarm control module.

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

If readings are incorrect:
Check lead between 5-pin connector position 2 and LED or 5-pin connector position 3 and sensor for short-circuit to supply as per WA5 See Other Fault-Tracing Test in Basic Alarm. Deal with fault or replace lead.