Broken wire in the door sleeve, most likely.

Door panel removal is a bit different on the rear door.

Pry the black plastic trim around the armrest off, unclip the door latch rod, then push the latch body forward until it comes free (or back, I can never remember until I have it in front of me -- it's obvious, at least!). Remove door latch.

Remove the 10mm screw at the top of the armrest, then the trim around the latch itself at the rear edge. Unscrew the lock button, then remove the ashtray and pry out the black plastic "cup" for the ashtray from the top. Complete panel will then lift straigt up and then away from the door.

Watch for the wires for the bottom courtesy light, they keep you from moving the panel very far until unhooked.

DO NOT pry the panel away from the door, you will break the prongs that hold it on and end up with a new door panel, not cheap!

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!