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  1. #1
    FEP Power Member fgross2006's Avatar
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    Default Aftermarket voltage gauge setup

    Last year I swapped my stock AMP gauge for a Volt gauge using the original gauge and having it re-fit to be a volt gauge. it fit right back into the cluster and looks stock.

    The instructions said to connect the power to a 12v key off source in the dash. It does light up the volt gauge and functions but I don't like the way it functions. Its actually getting a live voltage reading inside the dash, as opposed to an actual alternator charging voltage.

    When the car is running with nothing in the dash powered up the voltage reads 14- 14.5. Turn on the radio, it drops, turn on the heat, drops a lot, hit the directional and the volt gauge wiggles with each blink of the directional.

    I know from newer vehicles I have that came stock with volt gauge they don't behave this way. I was thinking if I wired it right o the battery I would get an actual charging voltage displayed but when the key is off I'd have a battery drain. Is there an inline relay I can install for a direct to battery hookup? Or a better place in the engine compartment to connect the power lead to the gauge to get a real voltage reading from the alternator?

  2. #2

    Default

    Remember those ammeter wires we talked about when you were getting ready to change out the gauge?
    Those go straight to the junction between the alternator and battery, and they already exist in the dash,
    right where you need them. The voltage differential between them is very small, so just pick one, and run
    it through the relay to the volt gauge.

    You might also want to consider running a separate ground connection.
    Cheers,
    Jeff Cook

    '85 GT Hatch, 5-speed T-Top, Eibachs, Konis, & ARE 5-Spokes ... '85 GT Vert, CFI/AOD, all factory...
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    And a 1-of-328 Deep Blue Pearl 2003 Marauder 4.6 DOHC, J-Mod, 4.10s and Lidio tune

  3. #3
    FEP Power Member fgross2006's Avatar
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    Default

    Quote Originally Posted by JACook View Post
    Remember those ammeter wires we talked about when you were getting ready to change out the gauge?
    Those go straight to the junction between the alternator and battery, and they already exist in the dash,
    right where you need them. The voltage differential between them is very small, so just pick one, and run
    it through the relay to the volt gauge.

    You might also want to consider running a separate ground connection.
    I didn't use either of the 2 ammeter wires because they are hot with key off. I was concerned about battery drainage.

  4. #4
    FEP Super Member cb84capri's Avatar
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    Default

    Install a relay and turn it on with the current ignition-switched 12v wire running to your gauge, than you can use the ammeter wire for a read on the voltage gauge and turn it off. I don't think the relay will care about a couple volts of fluctuation when you're hitting switches in the car.

    Cale

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