Heres a stab.

Try following the wires from the window. THere should be a connector nearby. With car off - check for continuity/resistance.

THen perhaps unplug it and put a test light on the wires to see your getting power back there.

__________________
Brian G.

1994 E320 Wagon with many warts SOLD
1995 E320 Wagon with a beauty mark or two FOR SALE