I have a '97 C230.  The left front window stopped working in the down
position.  Took the door panel off and applied external 12v to the window
motor and the window raised and closed properly.

I get NO voltage to the 2 wires going to the window motor.  Removed the
window switch panel expecting to find mechanical switches; however, the
switches are sealed and mounted on a printed circuit board so there is no
dirt in the contacts.  The fuses are OK.

I suspect the relay is bad but I don't know where it is located.  Can anyone
tell me?

Thanks.

Chuck