power window slams up

I would think that the track in the door may be out of alignment or bent due to the door being shut (the shock to the parts of being slammed over and over) and that could be causing it to close "harshly" have you removed the panel to see if this is the case, or if the glass is slightly out of alignment on the track?

What electrical part regulates how far the window goes up and down and where is it. I looked in the owner manual and can't find any relays assigned to the power window.

The power windows operate off an electrical window regulator located inside the door. Due to the age of your vehicle, check the weatherstrip around both sides of the glass at the base of the door and up along both sides and the top for wear or if a part is missing. If there is reduces friction between the glass and the insulation around it, it will cause the window to raise quickly.