I have a '97 E320 and the guages (speedometer, tach, etc) work once in awhile when the car is first stated. They will continue to work until the car is turned off. When the car is restarted, they stop. All the other dash lights, clock, odometer, etc always work. This just started happening a few months ago.
Any ideas on what could be wrong?
Thanks

 

Part failure of the pack is a known problem. eg Partial lighting.
However all readings going off is a different problem I believe.
Sounds like a CAN problem. The digital highway that provides data to the instrument pack.
The only simple solution I can suggest is to remove pack (special low cost tool required from eBay) is to disconnect and reconnect main plug ion back of pack.
The pack is also powered with more than one power feed. Possible one of these power supplies is intermittent. Try pulling the instrument pack fuses and refitting them This just might clear the problem.
This intermittent type problem is tricky to fix without getting into great detail.
Stuart