Betcha it's this:
There is a plastic piece on the window regulator that connects to the bottom of the window. This piece often cracks/breaks. Very easy to check:
1.) Remove the 3 screws holding the large speaker grill in the door. Disconnect and remove the speaker. There may be two more screws holding the speaker down. The tweeter speaker will remain in the door. Do not try and pry that small grill from the speaker.
2.) Remove 2 screws at the very bottom of the door panel.
3.) Remove 3 screws on inside/top of the door panel, right below mirror.
4.) Remove 1 screw on outside portion of door.
5.) Pop of the plastic piece that surrounds the door handle. Be careful here... I was able to get it off with just my fingers. Once it is remove, you will see 1 screw that needs removed.
6.) At this point, 'I THINK' all the screws that hold the door panel on have been removed. But double check. If any are left, they will be visible.
7.) Grab the door panel at the bottom, and lift up. It should pop of pretty easily. You will have to disconnect the tweeter speaker. A snap connection will be visible. A snap connector also operates the locking switch below the door handle. Unsnap this connection as well.
8.) You can now remove the door panel. Just remember which screw go in what holes. They are different lengths. Suggestion: After removing the door panel, put the screws back into the locations on the door panel (One or two twist), so you don't forget which screws go where when putting the door panel back on....
9.) You will now see a thin plastic covering with a weather sealing type material around it. You have to pull this plastic away from the door, to get a good view of the window regulator motor, etc... It will seal back in place when you are ready to put the door panel back on. The stripping stays very plyable and sticky.
10.) Now put your key in the on position, and operate the window up/down. You will probably see the plastic piece I am talking about. It will ride up/down on a track. Problem is, it is probably cracked and is no longer attached at the bottom of the window.
*** If what I described is accurate, you have to replace the window regulator motor. You can not just buy the plastic peice that cracked. I had my dealer do this repair (it is covered under extended warrantee), so I can't give you any info. on how to replace the unit.
*** Although this sound like it may take some time, you should have the door panel off in under 30 minutes. Just take your time removing the screws. You don't want to slip and gouge your door panel.
*** If you want an easier/quicker way to check without removing the door panel, do this (Will need another person to assist): Put your wife in the driver seat with the key in the on position. Go to the window that is broken. Look down into the door between the weather stripping (Use flashlight). Now have your wife run the window until a sound can to longer be heard. All the way up, all the way down. You will probably see this broken plastic piece running up/down. Remember, this piece has to be attached to the bottom of the window, hence the windows up/down movement.
Let me know if I'm right.... The procedure if fresh in my memory, since I just did it last week.
Later
P.S. - I have a '98 GTS as well, so the procedure should be identical.
