E36 Lessons of the day .... Power Windows:
The problem is with the motor shaft.
-- Lesson 1 --
This is how the motor works:
There is a magent on the spindle that determines when the window motor has stopped turning. When it figures out the motor has stopped turning it cuts the power to the motor... (this is how it determines when the window is fully up, or if there is an object blocking the window... such as a child's arm.)
The magnet has fallen (slipped) lower down the shaft so it thinks the motor is done turning all the time. You'll need to take off the liner for your door, take the screws off the motor and push it aside... in a little tiny hole in the bottom left corner where you can see the shaft in the door. Shine a light in there and you'll see the magnet.. use a tiny flat head and push the magnet back up. For extra precaution (what I've done)... put some contact cement on the tip of your screw driver and put some cement on the shaft below the magnet so it can't slip down again.
I can provide some diagrams and better instructions if you need.
-- Lesson 2 --
What Soldomatic is talking about is also a common problem with E36's... warn window tracks. It causes too much friction on the window, so it thinks there is an object blocking the window, so it stops. On the motor harness there is a butterly bracket which you can adjust with a wrench for the window shafts---90% of the time, this will adjust for the warn tracks.. if it doesn't, you'll need to replace them.
Before you replace though--- try using white grease.. (go to your local cdn tire, pep boys, etc... make sure it's WHITE GREASE --- that's the name of it).. and put it on the window tracks with a q-tip. Use a lot. wind the window up and wipe off any grease that's on the window with soapy water.
** note: you can usually tell the difference between the two problems using common sense. If the window stops in the same point(s) while winding up.. the problem is friction in certain points in the track. In which case you use white grease, or adjust the butterfly bracket.. or worst case scenario--replace the tracks. If it stops all the time on it's way up.. (i.e. moves up 3 inches, drops 1 inch.. --press button again-- moves up 3 inches, drops 1 inch... etc.etc.) then it's the magnet on the motor shaft.
-- Lesson 3 --
As for never having a one-touch feature, it's because your motor's timing has went off track. You need to reset the relay... do this by:
1) push down buttonall the way.. until window is down, hold button down for 10 seconds. (this sets the low)...
2) push upbutton---wind window up.. holding button down, not letting go... when window is up, keep button down for 10 seconds again. Ta-da.. your relay has been reset and your one-touch will work once again. (of course you can't do this until you resolve the problem with the magnet on your motor shaft first.)
supercharged.. you can bring your E36 over to my place, I'll fix it for ya if you're not comfortable cracking open your interior and playing with your motor... (I'm in Etobicoke)... otherwise, good luck.
and for anyone else.. as I said, if you need diagrams or more detailed instructions, just ask.