Tach only has Gray & Black Wires

[herefishyfishy]

I have a tach that came with the boat that's never been hooked up. I checked it out the other day and it only has a gray wire and a black wire coming from the housing. I know the black is for ground and the gray is for the sender, but isn't it supposed to have an ignition wire?

 

[R.Johnson]

Re: Tach only has Gray & Black Wires

No, the tach sense's off the alternator. If the tach has a light in it, there would be a purple wire to power that.