Alarm - Random Soundings

[gizard]

Has anyone elses alarm just decided to go off? is it possible that if the battery is getting old it might cause the alarm to go off? I know there is no knock sensor. The alarm went off this morning at 4.50am for no obvious reason and also on Friday evening. Normally the car lives in a garage so it's ok but it has been outside for a few days.... Anyone else had this problem?

PS - I don't have my manual with me, if you set the alarm/lock the doors by pressing the button and then press it again quickly you get a different tone - does this unset the alarm and just leave the car locked?

[amg merc]

They say check and regularly maintain (clean with WD40) the rear clamshell microswitch as this causes similar.

[m12_nathan]

Had it before, it was water ingress in the siren, others have had dodgy microswitches as has been mentioned.

[blot]

Mine seems to go off if the weather has been very hot, once car starts cooling, alarm fires up.