Phantom alarm triggering on VR Berlina

[SF7482]

Hey guys and gals,

Got an issue with a 1994 VR Berlina and its alarm system. For some reason, my alarm will be triggered in the middle of the night or day, by nothing at all. It has happened when it has been parked within a locked garage, when parked in the street, or even outside my front window!! I have even been outside in the garden when it has gone off, with nothing 'physically' triggering it.
One assumption I can make, is that it appears to be after I have washed the car at a Car Lovers Car wash or similar, where I have used a high pressure hose on the car. Is it a water issue? Or am I just a peanut?!

The only way I can combat the problem is to take out my horn fuse, but as you can guess I would like a more permanent fix which will allow the alarm to still sound if some low life tries his luck on my pride and joy.

Any suggestions ???
Any help would be greatly appreciated!

Thanks guys.

[Ash81x]

well what does the alarm say is triggering it? after the alarm has gone off, unlock it and jump in and watch your little red imobiliser light, it will flash a series of flashes, like it might do 3 flashes then a pause etc, each series of flashes is related to a different part of the car (boot, bonnet, doors etc), check your manual if u still have it cause it tells you what they mean.

I cant really set my alarm on the calais anymore as the boot switch is dodgy so it triggers all the time for no reason