Adjust '05 Ibiza FR alarm sensitivity?

[MW05]

My alarm doesn't go off by itself as a rule, but when we get a heavy downburst of rain it goes off.
Is there a way of desensitizing the alarm a little?

 

[RUM4MO]

I'd reckon that water is getting into part of that system and that is causing it to set the alarm off - but where?? Have you checked all over the car with a garden hose or pressure sprayer pack?

 

[MW05]

I don't think it's the amount of water, but the force. I used a pressure washer on it a couple of weeks ago. The only issue I had then was removing 90% of the clear lacquer from off the roof.
It only goes off when you get big drops or a sudden 'wet to your underkeks in ten feet' type of downpour.

It can rain all day and no alarm issues

 

[MW05]

Just changed the alternator between showers. Sat upstairs searching for wamasu eggs in Tamriel on the Xbox when a sudden burst of rain sets off the alarm...AGAIN!
Still annoying!