Having an issue with my tach and speedo meters.

It all started when I attempted to install the alta shift indicator. It began well however once I began taping the wires and started it up the rpm and speedometer failed to show my engine revs aswell as the shift indicator. I then thought that I had ran the tap wrong naturally. checked the taps. eventually pulled the taps and ran a multimeter. everything checked out, I then checked the fuse box nothing. now despite multimeter showing power readings the speedo and the tach still doesn't change. Anybody have any ideas. My next move I think would be to replace the wiring system for the tach and speedo.

trying to fix this issue myself and save some money rather than taking it to a mechanic.