1968 Under Dash Wiring Harness

[BigJim]

I am thinking about replacing the main under dash wiring harness. My car is a 302 J-code with C4 trans. It is not a GT car and does not have a factory tach. It does have the 2 inch tach mounted above the steering wheel between to two large gauge housings. For 68 Mustangs I see the following harnesses:

Non-GT no tach.
Non-GT with tach.
GT no tach.
GT with tach.

Which harness do I need?

 

[franklinair]

Non-GT no tach.
The after market Tach you're using is wired separately.

Neil

 

[Mosesatm]

Since GTs have fog lights I think you need the GT No-Tach harness.

 

[dalorzo_f]

Believe Mosesatm is correct, as the GT/CS came with fogs, that would use the "GT" one with fog harness.

If it was a big block manual, then it would need the tach (as it came stadnrd with the BB/manual AFAIK in '68) and if a tach option that would also require the GT/tach version.

So I'd agree GT-non/tach was the baseline. Unsure how a steering wheel mounted tach wires in, if same as factory and you want to keep it the tach one may be the go...

A messy mix and match!

 

[Mosesatm]

To expand a little on Neil's and Richard's comments - the OEM Ford tach was wired in series with the ignition system, meaning the car would stop running if the tach was removed without jumping the connections to each other.

I'm pretty sure that wire cannot be used for an aftermarket tach.

 

[franklinair]

My error:embarass:
GT harness for fog lites. (I should have remembered- the same error when I ordered the harness for my CS.)

Neil

 

[68 special]

Has anyone used Ron Francis for wiring?

The prices seem pretty good for a complete harness.

Not sure about the tail light harness plug.

http://www.ronfrancis.com/images/2016_RFW_Catalog.pdf


Bret

 

[retroman99]

I originally bought the Alloy metal products GT harness with tach because I thought I could use it with the aftermarket tach I was putting in the clock. turned out to be a bad idea. perhaps I could have made it work but the plugs are very different and I didn't feel I needed another challenge so I just bought the GT with fog no tach. when I layed the harness out next to my original it was a perfect match. i replaced most of the harnesses with alloy harnesses. not the cheapest but very little hassle.