I own a 2005 Chevy Suburban Z71 and when I filled my truck up one day, it was at empty, once I turned the truck back on, the needle went over full and facing down, why? Did the gears break in the dash board?

Thanks

 

google ipc stepper motor replacement

 

I agree with tech 2 , it is the stepper motor. GM had a lot of issues with the guages until like 2007-8 when they actually updated the stepper motors in the guages and then they stopped making the whole line in 2009.

 

Would it be possible that the stepper motors would cause the speedometer to not work if the fuel gauge is less than a half tank?

 

All 6 gauges have the same stepper motors and all 6 could fail from 2003 to 2007. They are easy to change if you can solder. You will have to remove the gauge cluster and disassemble it.

 

could be the stepper motor or it could be the sending unit. in my experience with the stepper motors (on my 04) they dont just read bad but will "forget" where home is and will rest lets say at half a tank and that will be if the tank is empty. if you fill it up your full would be straight down past full (6 o'clock). on my impala i had i think 4 out of the 6 not working right. speedo and oil pressure i think were the only two that did