Talk about timing! I just determined yesterday with the help of Bryan that the problem is the fuse strip. I had checked the the main fuse box and a small black box next to it containing 2 15amp fuses which I thought was the fuse strip, wrong!
The fuse strip is located about 12 inches directly towards the front of the car. It has two heavy guage black wires running into either side and the little plastic containter which flips open. Once you locate this, I am sure you will locate the problem, mine would still produce 0 ohms on a multimeter (meaning it was good, no "open") but as soon as I touched the strip with the probe, the grey area in the middle snapped!
Run down the Mercedes Dealer and pick up a couple, I think they run $.80 each.
Hope this is you problem.