Service warning messages on 2005 Mercedes-Benz CLK500

How do you reset the service warning message on the dash? I think you push the mileage reset button a certain way

That will most likely have to be done by the shop. Did you have the service performed?

Benzes are computer heavy, and I wouldn't be surprised if resetting the light needed to be done with a scan tool.
1 more answer
There is a procedure to reset the maintenance light that is quite complex. It must be attempted with the doors closed and is a 12 or 13 step procedure that involves pressing buttons on the dash to get a certain message displayed and then holding buttons for a certain amount of time with the ignition key in a certain position. Independent repair shops are generally helpful, perhaps next time you are getting your oil changed you could ask the shop to print out the procedure to reset the light. I have printed out maintenance reset procedures and tire pressure monitoring reset information for customers if they ask.