Detail: When you start the truck, the speedo does its thing and then gives a reading of 00. the speddo works perfectly, but the rest of the gauges dont even light up or anything. the tachometer, does constantly display the yellow and red over rev warning lights. but nothing else works in the dash.
Solution: It looks to me you need a new or remanufactured cluster but ... find a wiring diagram for that cluster and with a test light checks the + wires(sometimes there is more than one +) and the ground on the wiring diagram. You will need to remove the cluster itself for the backprobe wire's test at the cluster terminals. , Hi, a 6ya Mechanic can help you resolve that issue over the phone in a minute or two. Best thing about this new service is that you are never placed on hold and get to talk to real repair professionals here in the US. click here to Talk to a Mechanic (only for users in the US for now) and get all the help you need. Goodluck! , probally need to check engine groundwires. clean all terminals. battery may have loose terminal. , It could be a faulty dimmer switch. If the switch is fine then it might be a loose connection behind the gauge cluster. If you haven't pulled the the cluster off before. The plug is stationary and when you pull the cluster away it unplugs automatically. ButI would check the dimmer first. , chevy and gmc trucks have an on going problem with this,turn the key on,and get a rubber mallot or a hammer and hit the bottom of the fuel tank a couple of times,this will unstick something in the fuel pump/sending unit. , the sending unit inside the tank has a open circuit that will not complete the signal to the dash gage. The tank will have to be dropped to replace this. The fuel pump is also a part of the sending unit. The part is not very cheap neither , you need to scan this truck if you have a vss input to the computer then you have a bad trans or a bad vss sensor if no input you should also check the trans range sensor with the scan tool