VW 2000 New Beetle door sensor/car alarm goes off when doors open.

See if your dome lights work when opening the door. Usually a door latch.

From J.C. Moritz:

"OURCE:VW 2000 New Beetle door sensor/car alarm goes off when doors open.
I found a thread - http://forums.vwvortex.com/zerothread?id=1542461that details the repair of the soldering on the key lock door module. Our 2000 new beetle had the same issue. Also sometimes it refused to start. Soldering pins fixed it all.

Also see http://forums.vwvortex.com/zerothread?id=1015107 for releasing window from track, And door handle from inner panel.

I ripped the door apart and re-solderd the pins. I only had one pin with cracked solder but two others looked thin so I did them while I was in there. It's about a four or five hour project if you have all the tools. (8mm triple square also called an 8mm internal was the hardest to find - Also needed Torx T8 T10 T15 and T30 plus Philips Screw Driver. )
Project is difficult but not too bad for the mechanically inclined. A 7 on a scale of 10.
Since re-soldering pins - no more issues! My guess is that a VW dealer would get $200 for a new moduel plus 5 hours of service time for this gig - easily a $500 to $1000 bill. My cost - several new tools - about $25.00."

I know all rear doors on VW require two pulls, did you install the correct part #....some may have a child switch, is this in the correct position?

open driver side door AND trunk, then start car, this disables the alarm

remove the key from the ignition and press the UNLOCK. its saying the alarm was triggered, eg if door was opened without first using the unlock on the remote. maybe when alarm was armed not all doors were fully closed. or you just reconnected the battery so the door was open without you ever pressing the unlock on the remote(which could be called DISARM the alarm)

Try disconnecting the negative battery cable for 20 minutes and accessing the door.

use the remote to lock/unlock the car,it is not programmed to shut off the alarm when you use key in drivers door (it thinks its being stolen) and, no,you cannot reset/change it.

hmbn,m

Take to dealer. Vehicle needs vag-com to be reprogrammed. Bring all keys with you to dealer.

My 2000 Beetle does same thing (although not all the time). Just found an internet post that suggests there is a problem in the door lock sensor. I assume you are using a regular key - not
the keyless entry - like I am. He also said that you can disable the alarm (also disables the
keyless entry - which doesn't bother me) by leaving the front door AND the rear trunk open and
starting the car up. Seems to work so far. I will get the door lock sensor replaced and turn the
alarm system back on (not sure how yet), and let you know if that stops the problem.