I reinstalled my gauge cluster and my tach and volt meter thing stopped working

 

is it the combo tach and voltmeter in a single gauge? if so, then either the unit failed or its not connected.

if its the seperate gauges, then likely some power line isnt connected, and that power line powers the tach.

 

On the back of my tach there is 1 circular black connector, 1 circle white one, a little white one and a cable. Which is what? I think the cable is for the speedometer