I did a install on one a few years back- I'll try to remember. Three wires:
1. positive- hook up to a 12v non-constant (only when ign. is on)
2. ground- hook up to good ground
3. signal- has to be hooked up to the correct wire leading to your coil
under hood. I'm not sure what wire it is on your car, but the tach will
work when you connect the signal wire (and the positive/ground,obviously) A wiring diagram can be found in the back of a haynes manual.
if you have the autometer 5" monster tach and im sure with others there is 4 wires. You have the Black (ground). The white wire is for the lighting of the tach. Green is the tach signal. Red (positive).
Why would you put a tach on an automatic?? not knocking you or anything cause you could do whatever with your money but just curious.
i want to put a tach on my automatic for whenever i race(rarely) i know exactly when to shift manually, and donshift stuff like that.....plus maybe for looks
Its actually a pretty easy install. The part i found hard was just figuring out where to run the wires and where to mount the tach. I paid an additional $14.99 for a blue shift lens and blue shift lite cover. I think its worth it cause its matchin the color scheme i want.
Just something to think about. Also *off topic*, if youre into looks why not get a shift boot for your shifter to give the illusion of the 5 speed tranny?