Factory Tach Install Question

[tex_waco_usmc]

Ok, thanks to board member RatchetMaster I am the proud new owner of a tach dash for my daughters build. My only question is where does the wiring harness for the tach go through the firewall? Can someone send me a pic or describe the general location of where it passes through the firewall?

[Jonboy]

I would just find an existing grommet. You only need to put 1 wire through (tach signal). It will connect to the white wire that is hanging loose at your coil. The other two are power and ground; those should be labeled on the back side of the cluster as well.

[ray_mcavoy]

As Jonboy said, only one wire from the harness goes through the firewall. It's color will depend on the year of tach harness you have though. Early harnesses used a brown wire for the tach signal and they changed to white sometime in 1978 or 79.

The ones I've seen factory installed have the grommet already molded onto the tach signal wire. They go through a hole located about an inch or so below the lower right corner of the fusebox (as viewed from inside the truck). If you look closely at the firewall there will often be a factory stamped dimple where the hole needs to be drilled.

[Chaplain]

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