BlackIRON

Soo i had a problem with my car reading the fuel level so i swapped my 94 dash into a 96 dash no problems at all except that now i have no RPM's being read does anybody have a clue why? when i get out of work tommorow ima lay it all out and see. But has anybody ever run into this problem? i have seen other threads about broken RPM's and saying that you have to jump from the specific wire that is above the middle dash power connector but lets say i do not have said cable do i just have to throw the broken dash back on until i replace it?