I have 92 z-28 my speedometer works sometimes and sometimes it doesnt I changed the speedometer piece on side of transmission from another car I have to check that and it does the same thing. Today while driving it all my guages in dash quit working had blowed fuse replaced the fuse and blew it immediatley any suggestions on what this could be.
Thanks

 

You have a direct short somewhere.
Need to identify everything on that circuit , disconnect them all and plug back in one at a time to find where the problem is.
If that doesn't work then maybe a wire is cut and shorting the circuit out
You really need the FSM for your car with all the wiring diagrams