I hooked up a shift light in a 99 camaro and we couldnt get it to work so we decided to hook it up in the 7 and see what happend. There is three wire 12v ign ground and the green tach sensor wire. the direction say to hook it up to the ecu tach signal, which is what we did in the ls1 and it didnt work. so to hook it up in the seven i put the 12v and ground to my battery and the green tach wire to the tach signal wire(yellow) on the leading ignigter, the one in the check plug. so my question is if the light works like its supposed to then would the way i hooked it up in the 7 work?- is that the right wire for a good tach signal? I found it using the fsm- thanks

 

Screw the tach light, we've got a loud buzzer that lets us know to shift! >: D

 

Tach on the FC is Yellow/Blue found at the gauges, trailing coil, power steering computer, etc, etc.

It's found at just about everything that would need a engine signal.