1991 E32 740iL Problem

I have a problem with Mine i have a 1993 740Il and the RPM's Don't work and the Speedometer has a lag to it, as well as the temperature needle of the engine it does not state weather it cold or hot when i start the car it just barely goes up but doesn't show anything else.. Any Help?

The most likely cause is that the backup battery in the service indicator board has failed, The best solution is to buy a new si board from BMW, Trying to fit a non genuine battery is a waste of time as most times it will not work properly, You may be able to find re built boards elsewhere but again I have found that they are not very good, Peter

Thank you Appreciate it!