Tach Wiring

[Mattchu60]

Hello all,

I have a Autometer Tach to install in my 87' V10. What does everyone use for power source on these? I believe i need to tap into the lights, power and ground. Is there a common spot to connect all these wires? I'd prefer something which can be reached without tearing out the dash.

 

[chengny]

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Not for everyone - but I only look at the tach when I'm working on the motor.

Wire it like this:

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How you run the leads depends on where you intend to mount it. No matter what you decide, it is always going to look like an aftermarket tach.

Another reason it is in the engine compartment, is because I didn't want to destroy the factory look of the truck.

 

[Mattchu60]

Im not really looking for ideas on where to mount the tach - I plan on mounting it below the dash, under the radio. I am hoping someone can point out the places where I should be tapping into wiring. Should I pull switched power from the fusebox or somewhere else? How about the ground or lights? I just need some help on where to look. Thanks.

 

[Driver4r]

I have my power and light wired to the switched12v port on my fuse box.

 

[chengny]

I plan on mounting it below the dash, under the radio. I am hoping someone can point out the places where I should be tapping into wiring.

Good place to tie in to all the wiring you need. There should be a group of 3 wires in one plug feeding the radio (not the speaker wire plugs). The yellow is an ignition switched 12VDC, the gray is 0-12 VDC and is on the same lighting circuit as the dash/instruments and the black runs to the main grounding bus via a common splice. And you can drill a hole in the firewall to pick up the impulse signal from the distributor.

So:

GMC gray goes to Autogauge white
GMC yellow goes to AG red
GMC black goes to AG black
Extend the AG green to the distributor and tap into the white wire (not the pink)

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[Mattchu60]

Got the tach installed tonight, works great. Thanks all!