Tach wont work

ok so i hooked up my tach in my car today and now it is not working.......the shift light is on all the time but the tach doesnt not read the rpm"S....when i turn the car on it moves backwards but then just stays at 0...? any thouhgt of what it could be ..
:confused: :confused:

ttt...i would really like to get this fixed any suggestions

where did you get your tach signal from?

CHEVROLET, CAMARO, 1993, Tachometer

White-V6, red/black-V8. Location is front of left cylinder head for V6 and at a 4 pin plug at the passenger side valve cover for the V8.