Alarm going off at random

[IanOfYork]

The car alarm has been going off at random for some while. Unlocking the car and relocking it seems to shut it up *most* of the time.

I have checked the windows and the door switches and scanned for small creatures ... but there is no clear reason that I can find.

Any thoughts?

[Heidfirst]

Hi Ian, welcome to TOC 

Can you confirm whether this is for an Avensis (this forum) or a Prius as in your profile? & for whichever it's year?

You seem to have covered the usual bases except that another cause can be a failing Battery (most alarms have voltage drop as a trigger).

 

[xzirri]

Is it a Toyota alarm or an aftermarket like DEFA? I had a similar issue on my old Avensis with a DEFA, turned out to be a bad inline fuse holder. Also, believe it or not, cars parked close to the kitchen can have the alarm set off by the microwave.

[Owdjockey]

Might seem a stupid idea but check there are no insects trapped in the vehicle.