Same thing happened to me a little over a week ago. Filled up the tank and zeroed out the trip meter. Was driving home and noticed I was still on zero.

I called my mechanic and he said I had to take it to a speedo shop. None up in the high desert that work on MB. He gave me a name of a shop in Riverside and I called and left a message. Then I looked up the shop on BBB and it had an unsatisfactory rating. I called the MB dealer in Riverside (Walters) and found out they send their odometer repairs to the same shop. AND...they don't warranty the work they outsource to this shop. Interesting.

Anyway...I found a shop in Gardena, CA that had a great BBB rating. Called the guy and he quoted me over the phone $150. Made an appointment for Saturday and he fixed it in less than 2 hours and charged me $140. It was the gears. Works great now and have 1 yr warranty.

The shop is A-1 Electric & Speedometer. 310.217.0491--ask for Marcel. Very pleased with the whole experience.

BTW, the first shop returned my call and I told him that I was going to keep looking because his shop had an unsatisfactory rating with the BBB for failing to respond to complaints. He just said, okay. Not the least bit concerned.