w124 1994 300ce front window problem
 

did a search and found a lot on the rear regulator but not much on the front. the large gear on the regulator moves with the motor in both directions but the window is not participating in the action. window appears to be attached in all the correct places but i can't see behind the place where the large gear is to see what is broken. any help would be appreciated.

You need to add a mirror on a stick to your toolbox.
Seeing inside all that can be a real fun time.

you are probably right. i have a 94 sedan parts car that i can yank the reg out and see what makes it tick but i was hoping that someone had some info before i do that in case it can be fixed in the door

i found some pictures. it looks as if the arm is connected to the big gear with two small dowel-like protrusions. is it possible that these were sheared off or that the unit is distorted and the dowels slipped out of the holes?

found that indeed the arm is welded to the large gear on the regulator. the welds had broken and the gear was not connected to anything hence my window not working!
after removing the regulator (and confirming my hypothesis) i decided to try to fix this otherwise good regulator.
i drilled ten 1/8 holes ( the 3 original plus several others for added strength) and three larger holes through the arm and into the gear. being careful not to go through the gear and risk welding the arm and gear through to the regulator body and having it not move!
i mig welded through the arm to the gear in all the holes. the large holes allowed me to fill in a little more material.
i bench tested it after a couple tacks to make sure it would still operate, and it did.

the regulator on my car was riveted in with some massive rivets. i had to drill them out to remove the unit and do not own a rivet tool that would hold that size rivet.
i decided to use some spare 10mm nut/bolt set ups in the 3 holes to hold the reg to the door

everything is back in place and i now have an operational window:)