Your problem is in the cluster itself. Where are you located? I do clusters for these all day long and if you are not in Canada, I probably know someone close to you.
The GM 2003-2007 gauge stepper motors are known to fail, with pointers getting stuck. You can buy new gauge stepper motors Switec X27.168 and easy to replace.
If they were that easy my bench wouldn't be filled with ones that people have tried to repair themselves. I could show you some really neat soldering and new uses for solder wire lol. Amazing what people will try to do to save a buck.
