Car Alarms: Alarm goes off when its raining, valet mode, volkswagen passat

Question
I have been reading similar questions but I did not see any exactly like my problem.
I have a 2002 Volkswagen Passat.When it's raining and the car is parked up and locked the alarm goes off.(Flashing parking lights and a siren going off but no horn honking.So I guess this is an after market alarm.)But as soon as it stops raining the alarm stops going off as well.
I went to VW garage and they said that there might be some problem with the pollen filter seal and Water is getting to the CCU and causing me problems with the alarm.They also told me that it would cost me around £1500. But I'm just wondering if the water gets to the CCU, should not it cause more problems too (i.e. central locking & windows' etc..? Because everything else is working perfectly.It's just the alarm that's driving me crazy.

Any help would be appreciated!

Thanks!
Agnes


Answer
Don't be so quick to let them take your money Ms. A.
It sounds as if it's an after market system from
your description.

Probably dealership installed when
it was purchased originaly.

The shock/impact sensor seems to be the likely
culprit here.

It's usually to be found under the dash area,
blinking when anything taps on the underpanel.
Locate and either unplug or turn down.
To simply disarm it, locate and use the
valet/overide switch.

To start, look under the dash area for a button or,
a toggle switch. When you locate it, turn on the
ignition key, press and hold in the button (little
spring loaded micro button, red or black possibly)
until the alarm chirps 1 time. This should over ride
the system, and only the keyless entry part,
if installed, would still be operating.
The LED (light emiting diode) light in the dash
should also go on solid.=VALET/OVERIDE

This stops the alarm except for the keyless
entry if installed. The next step is to
either remove the alarm or, try to identify,
and get new remotes for it.

But once in Valet mode, it will allow the car
to start and operate like there was no alarm at all.

Let me know how it goes.

CHEERS.

ALARMTEK
CARALARMMAN.COM