Alarm Problem continues - Volvo S40

The Alarm goes off unpredictably in any period between a few hours and a
couple of days if the car's been parked that long.
It sounds for about a minute, resets, then may not go off again for many
hours more.
It's a 1998 S40 1.6xs and always kept in my garage. I haven't noticed the
alarm light indicate fault by rapid flashing as mentioned elsewhere.

I've checked the battery, various connectors, the fuse box, swapped relays
and the door/boot/bonnet switches seem ok. I'm unsure where the exact
alarm fuse or alam unit are located.

Is there any known issue with the S40 Alarm system?

Does the system record alarm events and what triggered them?
If necessary, can the alarm be disabled?

Any advice appreciated.

Regards,

Ide.

 

I have that issue when ever I get the alarm sensor switch adjustment wet
..I just spray wd40 in it and leave the bonnet \hood open on a warm day
or use a hair dryer to dry it out .

 

Thanks for that.

Where is the alarm sensor switch adjustment located?

Ide.

 

So far, I can find no sensor adjustment - only the alarm microswitch
integral with the well greased bonnet release machanism. It clicks but as
internal contacts could be contaminated, I've meantime disabled it
(connector by radiator) and central locking/alarm seem unaffacted.

No further false alarms - so far

Previous questions still stand and I'd appreciate any further advice on the
subject.

Regards,

Ide.

 

the alarm on my S40 or V40 went off without cause and the dealer replaced it
under warranty.

 

Did the dealer tell you if they had found a cause before replacing the
alarm?
How old is your car?

So far, so good - no further false alarms with that microswitch disconnected


Regards,

Ide.