Evalia Alarm Failure

I own an Evalia too and recall something similar. Have you checked the wiring harness near the siren? Moisture or corrosion can cause signal problems. Are there any warning lights, or just the alarm?

No warning lights, just the silent alarm. Where is this wiring harness located? Is it easy to access, or will I need to dismantle half the car?

I remember now, I had the same symptoms. After a lot of fiddling, it turned out to be a faulty connection. I'd suggest a workshop. It cost me 95€ to fix. They can diagnose it and replace the cable or plug if needed.

Thanks for the advice. I took it to a local shop, and you were right. It was a corroded connector. 90€ total, and the alarm is working again.