Need help!!!!

[Timothy Wazbinski]

I'm having issues with my RPMs reading on my speedometer gauge and I need to know how to fix it. I have a 1992 chevy GMT-400, silverado package. I've replaced the entire wiring harness inside the dash including the new dash with it, I've been told there could be grounds that may be not connected or not working properly but I've checked over everything and I haven't seen any ground out of place.

 

[618 Syndicate]

Are you saying that your speedometer needle rises and falls with rpm? What does the tachometer do?