In Reply to: Jumpy Temp Gauge posted by Bob on August 27, 1999 at 23:35:26:
I'm not sure about the E28, but in my E30 I had the same problem and it was the service indicater board. The SI board sits under the instrument cluster.
A good clue is if your service lights won't hold a reset. If your inspection light keeps coming on or flickers, it is probably the board. The ni-cad batteries that store the boards' memory fail after a few years and the board starts to fail a little later. You may start to notice problems with your other instruments as well.
Some people have had luck with soldering new ni-cads in, but usually the solder joints are weak as well and it doesn't always fix the problem. Programa sell rebuilts or you can get them new from parts houses. Mine cost about $125. Good luck