I have been trying to figure out how to get my tach running. I have read that there should be a connection on the back that was run out to the coil. I am trying to get a repo working and I have changed the printed circuit board its just that I cannot get this thing to work. I have pulled it back out of the dash and took some pictures just trying to figure out how to upload them. The orange appears to be the clock power but thats all I can get working.

http://s69.photobucket.com/albums/i56/foreverlookin/?sc=1&multi=4&addtype=local&media=image

can't see your pic, it wants a login...

Orange is clock power. I forget what color tach power is.

Do you have a guage conversion harness, or are you trying to make this work with the original non-guage dash harness alone?

Ignition power (which is what the tach needs) is present in the nonguage harness, find it and track it thru the pcb, see if it makes it to the tach.

Jim I bought all new wiring for gage and tach. I sent you some pics via email. Should there be a wire right off the back of the tach going out to the engine compartment?

Found the problem....followed your advise Jim and checked all power connections and found the PCB has an open before the tach power, who would figure? I bought it brand new! Anyway ran a new power feed from ignition circuit. Will test it tomorrow everyone in the house is asleep.

Thanks for the lead!

Tested it tonight tach works great!

way to go, steve!

Steve,

did you need to run a wire from the tac to the coil? If so, which post on the back of the tac did you use?

Brent I have all new wiring harness's on the car and they were specifically ordered for tach and console gages. Like I said earlier in this post I had no power to the tach as the PCB had a break in it. I ran a new power feed ACC/on, and that solved my problem.

My new engine harness wiring had an 16g brown wire out in the engine compartment which I just plugged into my MSD 6AL trigger output.

If you are not using a engine wiring harness for a tach I do remember that the clock power is the orange wire, the ACC/ignition on for tach power is the blue wire and the last connection (I forget the wire color) is the signal from your coil or MSD trigger output. You could run them direct to the tach if you do not have the engine wiring harness with the tach option.

Steve,

Do the wire colors you mention correspond to the wires within the tach or on the wire harness?

I only see posts on the back of my tach--no wires...

Brent

The wires correspond to the wires off of the back of the tach, internal. When I get home I could look at some pictures I took and tell you which terminals correspond to signal, power on, etc. The orange is the clock power in both the under dash wiring harness and on the internal tach wiring.

Steve,

I would really appreciate it if you get a chance to look at the tac pictures and tell me what colors correspond to what posts.

Thanks a million,
Brent

on the oer tachs you can see that. Orange is clock power, red is tach (ign) power, and I think blue is tach signal. Believe it's lower left as you look at the back of the guage. It's the one that does NOT have a connection on the tach PCB for the guage cluster.