Note that Mike said to "replace all the fuses" . MB fuses are known to have intermittant problems, so may look good and test good but still be bad . . .
FWIW, on the Ritter/Easley list, Marshall Booth recommends EVERY fuse in the car be replaced as a matter of course when your car hits its 10th birthday, since that's when these funny intermittant electrical glitches start to show up.
Might help, might not, but I'd go to the dealer and get some fuses and try it if it were me.