Mk4 Golf GTI 1.8 20V alarm fault

ok when we lock the car with the remote control and with the key the alarm goes off after about 20-30 secs. We can then open it and lock it again and it is ok. We have even tried leaving it open for it to get nicked but it locks itself after 30secs and then switches on the alarm. Has anyone else had this problem and do you know what i can do to fix it.

thats normal

when i say the alarm goes off, what i meant to say was the alarm activates for no reason apart from us locking the car.

you might have a faulty door latch. They are a common failure.