I have a question about the factory tach.

1. When adding the tach cluster to a truck that didn't have a tach originally, do I have to run new wires to the tach, or are they already in the harness????

In the factory manual, it says the same tach works for 6 or 8 cylinder engines. An extra wire is hooked up on the 8 cylinder tach to calibrate it. Very interesting!

I read the tach tips in the tech section, it was very helpful! Thanks, Scott

 

I would also like to know the answer to this because the cluster i have now has a tach and my truck originally didnt have one

 

All you ever wanted to know about factory tach's, and then some:
https://www.ford-trucks.com/forums/9...-question.html

 

The tach cluster is plug and play. No wiring needed. You may have to add the jumper wire like you said for a six or 8 cylinder though.

 

Normally the jumper wire isn't needed, however if there have been engine swaps, and the "Ignition harness" wasn't changed with the engine, then a jumper wire or cutting the 8 ground wire for V8 calibration is nessecery.

 

Everything should work as long as your factory wiring is working properly. If not, it's possible to wire the tach yourself, pretty much just like you'd wire up an aftermarket tach.

As you can read in that topic, I had quite a bit of trouble getting my tach to work. I wasn't getting power to the tach through the circuit film, so I ended up having to run a new wire to the B post (main power terminal on the tach) that's on with the key in ACC or RUN. Worked a charm, all the other factory wiring handled everything.

 

Thanks for the help!!!!!