1999 Oldsmobile Alero 1999 Alero Gauges maxed out

My Alero did the same thing after I put a new alternator in
My guess was there was a surge in the electrical
system and the little peg overshot the bar that was supposed to keep it back. I ended up drilling a small hole above peg and dragged it back into submission.
Has not been a problem since. Though taking the
dash apart would have been a cleaner solution.

I ended up having to take out the gauges, it was really easy. Disconnect your battery and undo two dash screws to remove the gauge cover and get to the gauge assembly, then four screws holding in the gauge assembly (two top, two bottom) and a little bit of twisting and turning it slid right out. Then you disconnect the the wiring from the back and unsnap the front glass off by holding down the black snap locks. The entire front piece comes off without drilling or hammering or destroying anything in anyway. Afterwards, just simply move the gauges back in a clockwise direction to where they're supposed to be. Then just put everything back in place in the reverse order. I took the car on a 1000 mile trip and haven't had any problems with it yet.