I beleive the wires are on both sides of the window. You access them by removing the interior panels adjacent to the window (left & right).
If this is correct, be extremely careful in removing the window and the gasket. The rubber gasket allows for the wire to run through it.
In attempting to replace a rear window rubber gasket I mistakenly pulled the wire off from the glass. There is virtually no way to reattach and have it work properly again.
Keep us posted,
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)