Pinpoint Test F: The Anti-Theft Alarm Horn Is Always On

Anti-Theft

Pinpoint Test F: The Anti-Theft Alarm Horn Is Always On

Normal Operation

The Body Control Module (BCM) receives voltage for the anti-theft alarm horn from the Battery Junction Box (BJB) fuse 6 (30A). When the perimeter alarm is activated, the BCM cycles voltage on and off to the horn causing the anti-theft horn output to cycle in conjunction with the turn signals flashing. The horn is case grounded.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors
- BCM

PINPOINT TEST F: THE ANTI-THEFT ALARM HORN IS ALWAYS ON

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F1 ISOLATE THE SHORT TO VOLTAGE

- Ignition OFF.
- Disconnect: BCM C2280C.
- Ignition ON.
- Does the anti-theft alarm horn continue to sound?

Yes
REPAIR circuit CRT02 (GY/VT) for a short to voltage. TEST the system for normal operation.

No
GO to F2.

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F2 CHECK FOR CORRECT BCM OPERATION

- Disconnect all the BCM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the BCM connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?

Yes
INSTALL a new BCM. REFER to Multifunction Electronic Modules Body Control Module (BCM). TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.

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