2004 Bonneville dash gages not working

[Ljwilds]

I heard it could be a ground. My gas gage is untrustworthy, always moving from full to E. Oil is off the meter. Battery seems right. Speedometer is good. My big concern is the gas. Could be related, passenger heated seat turns on and flips off.

[Sirius]

Oil gauge issue could be your sending unit (sensor) on the engine. Look in Techinfo for details.
Gas gauge could be the sending unit also. That's in the gas tank and a little more difficult to change, but not too bad.
Seat heater is likely a broken wire in the seat cover and probably unrelated to the instrument cluster. Check this Techinfo:

http://www.pontiacbonnevilleclub.com/fo ... 25179.html