W140 Driver's Door Problems

[plink49]

I have a number of problems with the driver's door (not the door itself) on my '92 500SEL, and I am thinking somehow they are inter-related. Trouble #1: Both speakers in the door don't work, about 90% of the time; trouble #2: The vacuum-assist door-closure is non-functional.....all other vacuum devices are fine; trouble #3: The door will not lock with the remote....all other doors and trunk lock/unlock just fine. Could this be a problem with tubing/wiring where it enters the hinge side of the door just because of age and obvious use of that door over 165,000 miles? If so, how does a person access that part of this vehicle to check, or for that matter, get the door panel off? I would appreciate some insight from anyone else who has seen these kinds of troubles.