Open the rear hatch, you can reach the fuel door release from the rear drivers corner inside the car. You can get your hand in far enough to feel a manual release on the electric one. This is assuming the dash mounted button isn't working. Which is located left of the steering wheel beside the hatch pop and choke.
behind the drivers door window
The 1985 Mercedes 380 SE has a gas door release latch located on the driver's side floor board near the hood release lever. If the gas door release latch is no longer operable, the cable to the door might be broken.
Gas door is on the deck lid.
There is a button on the dsh (left side of the wheel) it has a picture of a gas pump on it. If its not working there is a little tab and wire inside the trunk near the fuel door pull down on the tab to release the door. CHECK YOUR VALET SWITCH INSIDE YOUR GLOVE BOX IF ITS ON THEN YOUR TRUNK OR GAS RELEASE BUTTONS WONT WORK
Sounds like a faulty door switch on the drivers side.
There is no such switch you have to pull it carefully everytime you are about to pump gas
on my 1994 it's on the left hand side of the drivers seat next to the bottom of the door jam!
PUSH ON THE DOOR TO RELEASE THEN PULL OPEN
You'll need a professional locksmith to open the lock without damaging the lock and door .
Push in gas cap door it will release
Look under the dash, to the left of the steering column. You will find the lever to release the gas door cover.
You just push on the gas cap door. There is no remote release.