So I got an used Sunfire Cluster and took my '02 Cavalier dash part (the plastic is the worst, now have one screw holding on the front dash) and I got it all installed and when I went to start my car up, all the Sunfire gauges worked like they should but the odometer isn't working....Is there a way to fix that? Because my Cavalier odometer was working great before the swap.

Sounds like you got a bad cluster. There is no reason it wouldn't work if everything else is working.

You mean the light behind the odometer isn't lighting up?

Try smacking the top of the dash... hard.

yes, the light behind the odometer isn't lighting up and I'm really disappointed because I really liked the Sunfire Cluster...

I also reinstalled the Cavalier cluster because I'm the type of person that figures out the MPG a lot...