LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Volkswagen >> 1996 >> Passat GLS, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 4 (Anti-Theft System) >> Trouble Shooting >> Alarm System Will Not Switch On
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Alarm System Will Not Switch On

WARNING: This page is about a different car, the 1997 Volkswagen Passat. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ensure power window and central locking system fuses are okay. Ensure battery is fully charged. Check that trunk lid/rear hatch is closed and locked. Check that doors and hood are closed.
  2. Ground Circuit Check  - Obtain radio security code. Disconnect negative battery cable. Disconnect anti-theft control module 6-pin and 10-pin wiring harness connector. The anti-theft control module is located in driver's side fuse/relay panel. Connect ohmmeter negative lead to ground. Connect positive lead to anti-theft control module 10-pin wiring harness connector terminal No. 3. See WIRING DIAGRAMS  . If continuity is present, go to next step. If continuity is not present, repair open circuit.
  3. Power Circuit Check  - Connect negative battery cable. Connect voltmeter negative lead to ground. Connect positive lead to anti-theft control module 6-pin wiring harness connector terminal No. 3. Switch positive lead to anti-theft control module 10-pin wiring harness connector terminal No. 1. If 12 volts are present at both terminals, go to next step. If 12 volts are not present, repair open circuit.
  4. Leave voltmeter negative lead connected to ground. Connect positive lead to anti-theft control module 10-pin wiring harness connector terminal No. 4. Turn ignition on. If 12 volts are present, go to next step. If 12 volts are not present, repair open circuit.
  5. Alarm Horn Check  - Turn ignition off. Disconnect negative battery cable. Connect ohmmeter negative lead to ground. Connect positive lead to anti-theft control module 6-pin wiring harness connector terminal No. 4. If continuity is present, go to next step. If continuity is not present, repair open circuit. If circuit is okay, replace alarm horn.
  6. Door Lock Switch Check  - Connect negative battery cable. Connect voltmeter negative lead to ground. Connect positive lead to anti-theft control module 10-pin wiring harness connector terminal No. 7. Insert key in driver's door lock. Turn key to lock position and hold. Voltmeter should register 12 volts. Repeat procedure for passenger's door. If voltage is correct for each door, go to next step. If voltage is not correct, repair open circuit or replace switch.
  7. Connect voltmeter negative lead to ground. Connect positive lead to anti-theft control module 10-pin wiring harness connector terminal No. 6. Insert key in driver's door lock. Turn key to unlocked position and hold. Voltmeter should register 12 volts. Repeat procedure for passenger's door. If voltage is correct for each door, go to next step. If voltage is not correct, repair open circuit or replace switch.
  8. Alarm Switch & Hood Check  - Disconnect negative battery cable. Connect ohmmeter negative lead to ground. Connect positive lead, one after the other, to anti-theft control module 10-pin harness connector terminals No. 5, 8, 9, and 10. If continuity is present at one or more terminals, check for circuit short to ground. If circuit is okay, replace switch. If continuity is not present at all terminals, go to next step.
  9. Indicator Light Check  - Connect voltmeter negative lead to ground (10-amp DC range). Connect negative battery cable. Connect voltmeter positive lead to anti-theft control module 10-pin wiring harness connector terminal No. 2. If indicator light comes on, replace anti-theft control module. If indicator light does not come on, repair open circuit in wiring harness.
scientia non olet · About LEMON Manuals