Automatic window control switch problems 2000SL-2

With 68 K Mi on it the drivers window stopped responding to the control switch, bI bought a used one on E bay instakked it , tested it , worked fine, GREAT ! Few days later went by Micky D.s for a take out and could not close the window,,,It was raining hard poor me! Checked out the window regulatot and decided to replace it for $ 50 new! All worked well for about 15 cycles and then driver's window quit working. Took the original switch apart and found the contacts discolored (burn smudges), cleaned all soot off contacts, re assembled switch and now wondering how to proceed. The puzzle to me is why all of the circutry ain the switch box? It looks like enough stuff to run a small computer or audio system???
Any clues or suggestions? BTW "new" switches are not listed as far as I can find and used go from $50-150 with no guarantee except return refund..... Alpinebob