[medic911]

I have a 1988 930 (cab) with central locking.

Recently the system failed. If you attempt to use the key to lock it from either the drivers or passenger side, the doors lock, then spring back open again. This tells me that the system thinks one of the doors is open.

If you close the drivers side, then open the passenger side and reach in across the seat, you can manually lock the drivers side. Then you can manually lock the passenger side and if you hold the outside door latch open, you can close the passenger door and both sides stay locked. This seems to be the only way to lock the car.

The central button on the inside console seems to function fine.

My question is:
How do I discover which door is the problem and what do i need to do to fix/adjust the culprit part? Dont really want to take both door all apart for nothing.

thx