Weird W126 Lock Problem

[avatar218]

Hi all -- long story short:

My 1989 300SE (118K miles) has developed these symptoms which have so far baffled everyone:

1. Unlocking the trunk doesn't unlock anything else. I discovered this when I unlocked and opened the trunk and set off the car alarm; unlocking the driver's door turned it off.

2. Locking the passenger's door by key locks/unlocks that door only, not the trunk or other doors.

3. Driver's door locks/unlocks the trunk and other doors normally; however, the courtesy light doesn't work. (Coincidence?)

Any ideas? Thanks!

[greenacres2]

...but that sounds like mine at one time. Turned out to be the fuel filler door actuator that was leaking. Its next in line after the trunk, and reduced the vacuum to the rest of the system. Can't recall how i figured it out. The vacuum circles the vehicle counter-clockwise from the pump (near the spare tire in my car) and it's likely a vacuum leak between there and the drier door.
Coincidentally, I had a loose wire in my courtesy light, and it didb't work. A little solder and she's good as new. Good luck.