W140 door lock question

[sclassforever]

Hey guys. Here is my question; I have a 93 400SEL. Closing assist and central locking pumps dont work. I cannot move the lock mechanism of the drivers door by turning the key - there is no resistance. It works on the passenger side door. Is this normal? Would it work if I had a new closing assist pump? I replaced the batteries in my remote and I get the green and red light signals at the doors and trunk. I cant recall exactly when I lost my remote locking ability. I know the pump went out because I lost the reverse rods and lumbar. Im just perplexed why the passenger door lock will lock and unlock with a key, but drivers side just turns, and the lock wont budge. Its also frozen to move by hand unless im inside the care with door closed and engine running. Sounds like it might be a vacuum or hydraulic thing to me, and I had the door panel off and I have absolutely no idea how anyone could ever get inside there - there are no access holes at all.
I guess If I could get my remote opener to work again without buying a pump, id like to go that route. If I absolutely need a pump, I guess I would consider it. Or else I just live with it. Any advice is greatly appreciated as always. Still looking for another SD300..!

[mbdoc]

Most likely a seized door latch. There are linkages from both the door handle & the lock knob to that latch. IF they won't lock the door then that latch must be seized.