Questions on Wiring in Autometer Gauges in My 69 Charger

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8:07 AM
Dec 31, 2022
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Cannelton, Indiana
For my 69 Charger rebuild, I have elected to install a complete set of Autometer gauges in the dash.
I have wired up all the gauges using a Ron Frances cluster wiring harness, and am now in the process of splicing in that Ron Frances harness into my OEM wiring.

1. I have spliced in the now single Autometer gauge lighting wire into my OEM harness via one of the now unused ORANGE gauge lighting wires.
2. I have spliced in the Autometer Gas, Oil Pressure, and Water Temp sending unit wires onto the specific OEM wires that led to the original gauges.
3. I have one combined Autometer wire for the 12V Switched source set to the side until I identify what source of the OEM wiring I will use to splice into.

Now for my questions. My new Autometer Tachometer wiring diagram shows one wire going all the way to the negative side of the battery.
1. Is that required in order to avoid any potential interference from other components with the new tach?
2. Can I combine all the other Autometer gauge ground wires into the single wire to the battery, or will that potentially cause problems and I should just find a good ground under the dash?

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FBBO Gold Member
FBBO Gold Member
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9:07 AM
Apr 21, 2020
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Ishpeming, Mi.
A good clean ground under the dash for everything will be just fine. You could run a ground wire to the inner cowl kick panel area. That way your ground has a direct path to the body bypassing any other dash frame to cowl grounding which can become insulated with paint etc.