tachometer wiring in non tachometer car

[masternull]

throwing an amc original tach in replace of the digital clock.
this car is bare bones ( not even a radio )

I know the black wire goes directly to coil, but what should the brn/wht striped wire be hooked up to?

[BenM]

You need coil and ignition power. Unless it's for an older AMC.

[madmax4x4]

I wan to do the same thing but I have a yellow wire and a green wire coming from the tac and that's it?

[vangremlin]

I wan to do the same thing but I have a yellow wire and a green wire coming from the tac and that's it?

For an original AMC tach, you'll need to run a wire from the (-) post of the coil, and a switched power wire.  You may be able to use the power wire from the clock.  No ground is needed as the body of the tach will ground to the instrument cluster through the upper left screw. 

The older AMC tach's are notorious for failing.  Try and test it before you go to the trouble of pulling the dash out.  If the AMC tach is no good, you can install a Ford F-150 tach instead.  Here is a thread that describes the steps.

http://forums.amceaglesden.com/index.php?topic=38475.0

[carnuck]

The body does indeed need a good ground. IIRC, the 2 wire ones are aka tic toc tachs because of their inaccuracy at times. Most were pulled for rev limiter versions. Green to coil negative (if it's hooked up correctly. Test which side has power with 1 wire off first) Yellow to dash lights. I found several of my old 60s/70s tachs and vacuum gauges in a box awhile ago that I plan to post for sale eventually (when I can access my cabin to get them)

[vangremlin]

The ground comes from screwing the tach to the instrument cluster. The back of the tach is metal, and the upper left screw contacts the circuit board that traces to a ground. No need for a separate wire.  This is the way it came from the factory.

[carnuck]

The green wire isn't a ground. It's the signal for the tach.

[madmax4x4]

Good thing is I already have the dash out trying to figure out how to hook my A/C up. I don't think I have a normal coil anymore because it's the all in one unit. I'll see if I can post a pick.

[madmax4x4]

I'll get a better pic tomorrow it's an automatic so I guess I don't really need a tac but I already had one from another cluster. And my clock wasn't working