Tach not working water temp gauge peg's

[krienen]

I have a 1972 rs Camaro the tach work's ,but when you cut the headlights on it stops and the water temp gauge peg's .I rewired the car with a American autowire kit. I think it's a ground problem . but don't know where to start . any help would be helpful
tahnks

 

[DAWG]

retrace all your wires?
recheck every ground
if that don't work call American autowire.