ive just bought a 1999 a4 and when it gets dark the alarm goes off every 20 minuites or so.
How can i shut it off?

 

You need to replace the motion sensor on the dash

 

cheers mate I'll give it a go!

 

ive disconnected the stupid little beep beep siren but the lights are still flashing, ive changed the motion sensor on the dash but now ive had to take out the fuse for the hazards.
Where is the main alarm located so i disconnect the power going to it??????

 

is this with your windows open?