Hey, I have a 1998 c280 mercedes benz. All of a sudden, the wipers, the directionals, the windows, the sunroof and the trunk will not work at all. The trunk will not open with the manual key. The drivers side window will go down with the manual key in the door.It was suggested to me that i switch the k40 relay, with I did and no results. There has to be something that I am missing. any ideas? please help.

 

First off, have you checked ALL fuses? There are fuses under the hood, on the side of the dash & in the trunk.
Is your central locking functioning properly?
K40 is the designation for a relay unit. There are several in this vehicle.
Which one did you replace?
Everything that is not functioning runs through the l/f sam. has this been tested?