HELP 76 dart gas an temp gauges wont work!!!

I know this should be a easy fix for some but I'm new to wiring for gauges. I was told by two mechanics that the reason my 76 darts gauges dont work is cause they are bad or broken gauges. Ive noticed the car has wires clipped here an there throughout, some that I can see hanging under the dash. The three that I can see easily are two yellow wires coming out from the harness tape and one red wire that is a few inches poking out and cut off behind the yellow two. The car runs and drives just fine minus the two gauges.