1988 528E, 6 cyl, the door locks by using the key and turning. The driver door lock, but did not return to the vertical position after it is locked. It is stuck in the horizontal position and will not turn using the key. The passenger side will open with the key from the outside, the inside can open the driver door. How can I repair this?
The door panel needs to be removed to look at the operation of the door lock of the driver's door.
It could be the door lock actuator or an electrical circuit problem.
Remove the door panel first and check the door lock actuator to make sure there is no mechanical failure first before you go any further. If that is O.K. then proceed with the electrical diagnosis.