Alarm with mind of its own...won't switch off

[asd2001]

Up until now never had any issues with my alarm (97 400)
I never set alarm in the garage. it was unset but went out tonight to the garage and found the alarm going off - sounder going off and cycling through annoying noises and indicators flashing. just as well sounder is very quiet!
It won't switch off with the key fob but doors will open and close ok and car will start.
Any ideas on how I can get it to shut up / fix?

Thanks
Andrew

Edited by asd2001 on Tuesday 30th May 20:22

[Chimp871]

Unplug alarm siren then bench test it. Water may got in.

[asd2001]

Thanks - wish I'd read your suggestion before following advice to disconnect battery to reset....

Sounder looks ok but connector damp and copper green. Disconnected now and all back to normal. I'll let the connector dry off, give it a clean up and test. Also found out what the tiny key on my keyring was for - properly noisy!!!