My passenger quarter window does not move up/down. The 3 bolts that hold the glass are still in tact. I noticed that there's a 4th hole on the glass without any bolt or washer. Is there supposed to be a 4th bolt holding the glass? I assume no, but I may be wrong. When power is applied to the move the window up or down, I hear the motor is running, but seems like it's not engaging the track to move the glass. Is there some kind of cable that is attached to move the glass frame? Any clue is really appreciated. thx.