The instrument cluster is totally dead in my car, no guages function and no lights work. Is the odometer memory within the cluster? Does this mean that most likely the odometer reading is lost or if I install a used cluster it would show the correct mileage again? I'll post this separately but is the cluster repairable? Is this a common problem?

a used cluster cannot be installed from another s-class. the clusters are vehicle specific, they are ordered by vin number and the vin number is programmed into the unit and cannot be erased by any conventional means. if you install a used one you will have other problems due to coding conflicts, the mileage will display incorrectly or not at all may look like this - - - - - - as for the mileage when a new one is orderd from the dealer they charge a coding fee of $25 to set the correct mileage. if the mileage is unknown they go by the last service record on file or they extract it from the cluster memory, if they can communicate with the defective unit.. try to go with a new one. if you do get a new one have the dealer or other shop that has the mercedes star diagnosis system install it.
it is needed to correctly version code the unit after installation.
Ray
mercedessd@cox.net