Car alarm goes off sponteneously?

[PlantKiller]

Our Fiat Multipla's car alarm goes off between 9.30 pm and 11.30 pm most nights.

Any idea what causes it - we are off road and it has only started happening during this recent hot spell?

[Toureman]

When I was a chauffeur in London I had a radio intercom in my car, I found out that I could set of some alarms by simply keying my radio mike, could be a regular taxi pick up near you.

[Ethel]

Could you have a moth, cranefly or suchlike inside the car that starts flying when it gets darker?

[Toureman]

Never thought of that Ethel, could be that! how do I get rid of a dessicated cranefly in one of my sealed headlights?

[tubeway]

If you have a Multipla I think that the alarm is the least of your problems

[homer75]

Might be an intermittent fault in one of the microswitches - start by isolating the taligate then the bonnet as these are the easiest ones to get at. The door switches will be in the lock areas and are difficult to access. Pull the connector off the switch you are trying and short it out with a bit of silver paper so that is sees a 'closed switch' - If you are lucky it will be in the tailgate or bonnet connection.

[spaced]

a friend of mine had the same problem when it rained or was really hot. The rain water or water (condensation) in the heat was trickling onto the alarm connections under the bonnet and was setting of the alarm.