Tach Dash conversion - 94 GMC

[Willie Makeit]

Gents,

What is involved in adding a tach dash to a non-tach dash truck (94 GMC)? Is the coil to gage/tach wire already there? How difficult to swap out odometer? What do I need to know? Would love to add a tach cluster to my truck but unsure of what all is or isn't in there.

Thanks!

[Palf70Step]

I have heard of people changing them over, but not sure what is involved. Hopefully one of the more knowledgeable folks can provide you the details.

[HondaMartin]

I would like to know also!

[Drewkimble48]

I literally just swapped my non tach gauge cluster to one with a tach for my 93 gmc last weekend. It was pretty easy to do actually. Pull your old one out and install the new one. Our trucks are already wired for the tach regardless if the truck didn't come with it. I got my cluster out of a 94 truck just to let you know.
as far as turning the odometer, YOu just break the gauge face plate from the shell and and turn it over to see two screws for the odometer.

I think but, don't hold this against me, when My brother and I did it, we think that the needles did not have to come of the gauge plate but, just look it over before pulling it apart. I will say though it is a lot easier and safer to take the needles off instead of getting them bumped or dropped and break them off...

[HondaMartin]

Originally Posted by Drewkimble48

I literally just swapped my non tach gauge cluster to one with a tach for my 93 gmc last weekend. It was pretty easy to do actually. Pull your old one out and install the new one. Our trucks are already wired for the tach regardless if the truck didn't come with it. I got my cluster out of a 94 truck just to let you know.
as far as turning the odometer, YOu just break the gauge face plate from the shell and and turn it over to see two screws for the odometer.

I think but, don't hold this against me, when My brother and I did it, we think that the needles did not have to come of the gauge plate but, just look it over before pulling it apart. I will say though it is a lot easier and safer to take the needles off instead of getting them bumped or dropped and break them off...

Do you know what wire it is for the tach? Im just adding a stand-alone tach and want to use the original wire. Is it the white wire coming from the distributor the nothing is plugged into?

[ChevyTech]

Originally Posted by HondaMartin

Do you know what wire it is for the tach? Im just adding a stand-alone tach and want to use the original wire. Is it the white wire coming from the distributor the nothing is plugged into?

My understanding is all the 1992 and later trucks had the wiring there for the tachometer and all you need to do the swap to a tachometer instrument panel.

Note: when buying an instrument panel make sure you buy one from a truck that has the same number of cylinders as your truck. There is a difference between a V6 tach instrument panel and a V8 tach instrument panel.

From the 1993 wiring schematic manual:
Circuit 121 is for the tachometer. The wire color is white.

Circuit 121 is in cavity “T” in the instrument panel connector.

There is a gap in the middle of the instrument panel connector. One end has seven cavities on each side and the other end has six cavities one each side. Cavity “T” is the closest cavity to the the center on the end with seven cavities. The wire color should be white.

The white wire by the coil with nothing plugged into it connects to the same circuit that goes up to the instrument panel tachometer.

[HondaMartin]

Originally Posted by ChevyTech

My understanding is all the 1992 and later trucks had the wiring there for the tachometer and all you need to do the swap to a tachometer instrument panel.

Note: when buying an instrument panel make sure you buy one from a truck that has the same number of cylinders as your truck. There is a difference between a V6 tach instrument panel and a V8 tach instrument panel.

From the 1993 wiring schematic manual:
Circuit 121 is for the tachometer. The wire color is white.

Circuit 121 is in cavity “T” in the instrument panel connector.

There is a gap in the middle of the instrument panel connector. One end has seven cavities on each side and the other end has six cavities one each side. Cavity “T” is the closest cavity to the the center on the end with seven cavities. The wire color should be white.

The white wire by the coil with nothing plugged into it connects to the same circuit that goes up to the instrument panel tachometer.

Thank you ChevyTech!!!!

[ChevyTech]

Originally Posted by HondaMartin

Thank you ChevyTech!!!!

You're welcome.