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Keyed On +12v Source


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I'm installing Autometer gauges in my truck. I have 3 wires I need to hook up.

+12v Keyed on (ignition) source
Instrument Cluster light source (would like to be able to dim these gauges as well with the factory dimmer switch)

There is a write up on another forum of a guy using the door ajar speaker plug in port & just using a flat blade connector to tap into that. While this works, it's not factory & it just doesn't look very good. I would also like to be able to retain the door buzzer.

So I'm looking for a keyed 12v source under the dash somewhere. I do not want to tap into the radio. Reason being when I flip the key backwards to turn on the radio, it would turn on the gauges & drain the battery even quicker. So looking for keyed 12v source other than the radio.

I've been trying to figure out which wire to use that would work in conjunction with the light instrument cluster dimmer. I heard the gray wire that comes out of the headlight switch itself is the dimmer wire? I believe I can use the illumination wire from the radio at this point? I believe that's a dimmable source?

Alright, so this might sound obvious. But I'm looking for a good ground in cab. If there is such a thing. I was originally going to use the ground screw that is right next to the obd2 port. However I don't believe that's a very good ground. Anyone else have a good in cab ground they use? Thinking of running the ground down next to the hood release switch & running a self tapper into the sheet metal there.

Anyways. Thanks guys!

ak diesel driver

6.5 driver
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I used an add a tap to a fuse on the side of the dash. All wiring is hidden behind the cover. The steel bar that goes across under the steering column is kinda the main grounding spor


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I found +12v on ignition in the convenience center.

Im not quite sure about the dash lighting power - perhaps the hvac control would be an easy place to tap it?

As for grounds, its a question about whats the easiest, I guess!? Self tapper into the closest sheet metal should do the trick. :)