weatherstrip

the weatherstrip/trim on the upper left corner of my rear glass has begun to "peel" or pull away from the glass. I've got an attractive piece of electrical tape between the trim and the vehicle to try to prevent water from entering the vehicle. Is my window in need of replacement or can I just have my window removed and reinstalled with new trim/seal? If anyone has any suggestions on how to repair this please let me know. :banghead: I know this has happened to someone else...I've seen it.