Hi, The alarm went on when one of my kids opened the back door before I did. Now I can't get it to turn off. I've tryed locking and unlocking the driver's door several times, starting and driving, letting it stay on. I've tried disconnecting the battery for a long time (it still comes on every so often and beeps for a while after I connect the battery). I finally removed fuzes until it turned off, but the fuse also controls other things that I need. When I insert the fuse it starts beeping again. Is there anyway to reset it? or is the central locking system broken?

If the ssystem is a MB system it should reset by switching the car on and off.

Is it a MB system or aftermarket??

__________________
1988 W126 420 SE

beware of fundamentalists!

Yes, it is a stock MB central locking/ Alarm system. I have tried starting and turning off the car several times as well. Maybe it would help if I knew where the module is located.

On my 1990 300se, the alarm module is located behind a black plastic panel on the passenger's side towards the firewall, which you will see after removing the floor mats and carpeting. Not sure if it is the same on your car.

Have you replaced it? How expensive is it?

For those who have a similar problem, this is how I solved it.
It seems that opening the drivers or passenger doors with the key can cause the alarm to go off. I now always open the trunk first which opens all the locks.
If the alarm ever goes off, this is how I reset it.

1) Remove the alarm fuse. (number 15)
2) manually lock and shut all the doors
3) lock the trunk with the key
4) have someone hold the hood switch closed or tape it down so that the alarm system thinks the hood is closed.
5) connect the fuse
6) open the trunk which should unlock the doors
7) release hood open switch

At this point I can lock the car with the door key and all doors lock. I only open the car by opening the trunk first and I have never had a problem with the alarm going off.