Tach

[zglad]

Does anyone know how to wire a factory tach that has two 10-12 gauge wires that are both red. Neither one has a stripe on it. Can it be hooked up backwards? I have the wiring from the coil, but I just don't know how to attach it to the tach. '79 CJ-5.

Thanks
Zac

[jps4jeep]

10-12 gauge wires? Those are some big wires for a tach, usually they only run a 18 guage at the most. most after markets are 20 guage. A tach is pretty simple to wire up. just need to be sure about what you got. The most basic tach will have nothing more than a threaded adaper that looks a lot like a speedo attachment but smaller, these are the old mechanical tachs, the most simplest electric tach would have two wires, one to receive the signal from the coil and one to revieve 12 volts. the tach would have to be mounted on metal cause it uses this as a ground. These were common in vehicles with metal dashes (early 60's GMC's with factory tach option) or some vehicles that had them on the hood. this sounds like what you got. I am not too sure if the CJ tach was like this though. CJ's had metal dashes right.

[zglad]

Yes they do have metal dashes, but they don't ground using the dash because the housing is plastic. I know that a 12 gauge wire sounds really big but I promise that is what is on there. I guess I need to be more specific about my question. Can the two identical wires be hooked up incorrectly? If I run the negative feed off of the coil to the wrong one will I do any damage. I have seen numerous tach wiring diagrams for a tach like mine, but they all have one of the wires marked so it is easy to tell what wire to connect to it. Mine doesn't.