348 door jammed shut

Hi, l have a 1990 348 tb, generally in good order but the passenger door won't open. It was previously fine, but not now. I've read the threads on how to open by winding the window down and pressing the lever inside with a screwdriver but this doesn' work. It seems to lock and unlock OK, and the internal release cable is attached and seems to work, and using the external push button the mechanism inside seems to be working but the door doesn't release. I looked at the (working) drivers side and noticed that the sliding plate (almost hidden) that I think must actually open the latch only has to move about half the distance to open the door compared to the passenger side, which moves the full length of the slot but still doesn't open.

Has anyone got any ideas? I was wondering if even though the lock / unlock sounds like it is working, is it possible for something inside to break so it stays locked?

Any advice would be gratefully received because I'm struggling to work it out!

 

After several hours peering down the narrow gap between the windows seals with a USB mini-camera and lots of prodding I have now fixed this. Thank you for everyone's replies - I think my problem was different (see below), but by working through all of your suggestions I eventually worked out what the problem was.

While comparing the latch on the drivers-side (which works fine) with the passenger-side which was jammed, and while pulling the inside door release catch repeatedly so I could watch the mechanism move, if you look at where the cable attaches to the lock mechanism with the white clip, you will see that the metal the white clip attaches to slides up and down in a slot.

Now, on the driver-side (which works), when the door is open or closed and without touching the inner release handle (or the outside push-button), the metal that the white clip attaches to should be at the top of the slot, and not half-way up the slot as it was on my jammed passenger-door. Also when you pull the inner release lever or push the outside button, the metal that the white clip attaches to should slide to the bottom of the slot.

I noticed that on my jammed door it was always in the middle of the slot and was not returning to the top. After much studying with the USB mini camera (which cost £5 off ebay and has been my saviour on this job because you can feed it down inside the door for a better view, and it has lights to see what you are doing) I noticed that the cable that comes from the inner door release and enters the latch assembly at the bottom was not seated properly, and this was stopping the mechanism returning to the top of the slot. Next, with a very long screwdriver I gently levered and prodded the cable outer where it attaches to the latch (this is really fiddly because it is on the bottom of the mechanism and you are working through the window slot), but after a few minutes I head a reassuring thud as the cable outer returned to it's correct seating, and could see the mechanism was now at the top of the slot, and voila the door now opens!

Thinking back, last year the passenger-side window jammed half-way down one day, but was then OK so I thought nothing of it. I now suspect that it somehow tangled with the door release cable to cause the jamming, and that was probably the start of my problem even though the door lock didn't jam until a few month later.

I hope this description helps somebody else who experiences the same problem in the future!