VW Passat alarm problems

[eastern]

I have a 2002 Passat estate with the factory fitted alarm. For some reason the Alarm has started going off at night for no apparent reason. I have checked all windows are shut, all doors closed properly and all the other obvious things but still it keeps going off. I know there is a button on the the side post to switch off the interior sensors but that makes no difference. I am now having to leave doors unlocked at night as this is the only way I can park the car without it going off. I have it booked into VW for diagnostic on monday but was wondering if there were any VW owners/mechanics who might have come across this problem themselves and how they rectified it. Thanks in advance.

[MiniMadTez]

I have an Audi estate with exactly the same problem......Audi wanted crazy money to look at it so my dad disconnected the horn from the alarm,but my hazard lights still went off all night so I just took out the fuse so I can lock the doors but have no alarm. My car is locked, no alarm, but it has stopped the neighbours complaining.
Problem with that (apart from having no alarm) is that the fuse is the same one for my interior light, so I currently have no interior light which can be a pain.

It could me a number of things.....faulty sensors etc....but diagnostics, or pulling out the fuse are the only options I know! :)

[eastern]

Thanks i will try the fuse if the diagnostic doesnt cure it. I was just thinking with all the cold damp weather if one of the door switches is the problem as it doesn't appear to be the ultrasonic sensors.

[eastern]

Just out of interest in case anyone is following this. I had the diagnostic done and its the boot lid lock thats corroded, hopefully will be ok when thats replaced.

[Chazlenor]

FWIW: I have this problem right now!!
In order to lock the car without putting alarm on I have un-locked the car, entered from the passenger side, clicked the internal lock button and then got out of the passenger side. My car is now locked, without alarm on. Now I just need to investigate if the boot lock is my problem or not.

[mikeybhoy67]

Its 3.30am and I have just spent half an hour in my car reading the jibberish in the book about the alarm. I bought the car 3 months ago brand new and the alarm was going off all last night so i took it to the garage today (yesterday!) and the guy told me the sensetivity was set at 100% so he reduced it to 70%. That obviously hasnt worked. I have now locked the car after pressing the button you speak of, and its been 20mins of silence..... Hopefully that has done the trick.

[coldkiwi]

Hi,

I've had this issue as well. My alarm would go off for no reason. Didn't have the issue in summer, just in winters and Autumns after periods of wet weather. I used the same trick described above to disable the alarm (locking the car from the inside via the passenger door).

I came back from a long holiday to find my car completely dead an inch of water in the rear passenger footwell, turns out I had the dreaded water leak issue (google "water rear passenger footwell"). The seal around the pollen filter had failed (Im amazed it worked in the first place as it was made of foam), and water had leaked into the car and was playing havoc with the electrics. There is a electronic control module (The CCU, or convenience control unit) in the front passenger footwell which had got very damp and the connections had corroded. It helps control a lot of things.. Windows, fuel flap, interior lights, boot release, remote locking and the Alarm, all of which are not not working on my car.

Anyway, I would recommend that any VW owner with a car in the 1999 - 2003 range having alarm issues check the passenger undercarpet for dampness. You can also check the foam that is behind the glovebox against the bulkhead for damp. (You might have to pull the carpet back slightly. When I squeezed it on my car rivulet of water came out. It might save you a lot of cost...