Silverado guage problems

:banghead: I have a 99 silverado LT, the guages are all goofed up, the tach reads aprox. 500 rpm higher then it should, the speedo sometiems moves but is incorrect, usually it stays at 10mph when stopped. The fuel gauge usually reads an eigth of a tank at all times. Oil pressure seems to be the only one that works. my cruise control and high beam lights are on all the time. The craziest part is the odometer 90% of the time it is blank, sometimes it reads 388,*** miles(which it is not close to) i would guess it has 110K, and when the odometer isnt reading those things, the trip meter works, but then you switch it back over to the odo. if reads 000000. If anyone could help I would appreciate it. I am guessing it is either the gauge cluster itself or the computer, id like to know for sure before i start buying unnessicary parts. Oh and this has been happening for about the past year or so. Another issue is that sometimes the battery will be dead after sitting overnight, but other times it will sit for a week and fire right up. It has a new battery and alternator, so something is pulling amps when its is off and locked up

Sounds like you may have a voltage regulator problem. Not sure if it is located in the alternator or not though. Wife had a similar problem with her Grand Prix, gauges were all whacked out, intermittent dead battery. Cause was a bad alternator (bad voltage regulator inside the alternator). Just an idea.

Dont quote me on it last time i saw gauges do that i had to change the main computer and it fixed the problem. if you can take it to a dealer or auto zone and if the scanner brings up alot of codes we call them lottery numbers, cause when the computer goes bad it brings up all kinds of crazy codes.

check the recalls chevy has had a lot of gage clusters go bad.