The system arms when the battery is reconnected, but the horn doesn't sound. Unlock a front door with the key to turn the alarm off. If that doesn't work from one of the doors, suspect there are broken or frayed wires between the door hinges.
Standard practice is to use some type of memory saver device while replacing the battery or while the cables are disconnected for some other service.
https://www.2carpros.com/articles/how-to-reset-a-security-system
This is much more important on newer models where multiple computers will lock up, requiring a tow to the dealer. VW and BMW are the worst offenders at this designed-in nightmare.
Sep 8, 2021 at 9:16 AM
