power seat won't move forward
 

1990 300SE--All of a sudden, the passenger seat won't move forward. Moves in every other direction, (including head rest), but get nothing when moving switch forward.

Seems like the switch on the door is the first place to check--but looking for advice.

If I need to get to the back of the switch on the door, how do I do it?

Some models you can take the trim from around the switch and see the two phillips head screws and just remove them and remove the switch. Otherwise you will have to remove the door panel. I have seen where the car was sent to a detail shop and the plug underneath the seat was knocked off by a vacuum cleaner wand. I spent two hours of my life searching to the problem before I found what was wrong. Hope this helps.

I just had this problem to. there are 2 seat fuses under the hood
sometimes 1 blows and 1 is good. Good luck.

There are 2 fuses per seat indeed...1 might be blown.

On my 300SL I have the same problem...sometimes my seat doesn't slide forwards/backwards...the problem in the SL is caused by the seat computer/regulator.
Although the W140 and R129 share a lot of parts, I am not sure whether your W140 has an additional computer for the seat adjustment.

greetingz,

I'd try squirting a shot of WD-40 into the slot behind the offending knob...if you can get the liquid into the switch, it'll likely make the switch work for a while. I somehow got an extra year or so out of a seat switch that way.

Good luck!