Dash/Cluster wiring for "Econo" light

Discussion in 'Technical' started by leeinphx, Jan 25, 2023.

  1. leeinphx

    leeinphx Member

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    So I'm trying to clean up the under dash wiring on my '75. Going with an aftermarket dash gauge system so no longer have need for the warning lights. I've figured out how to get the oil and water temp sensors wiring separated to give readings versus triggering a light.

    Now I'm chasing a few other wires to see where they originate from to see if I can take them out. One is the Econo light. The wire is black with what appears to be light blue dashed colors. The wire goes from the cluster circuit board Pin 10 to the ignition switch connector on a pin adjacent to the yellow wire. My wiring diagram does not show that pin being used on the ignition switch.

    The dash harness pin at the ignition switch connector had a second wire coming out that now goes no where (same colors). I have to assume it was for the seatbelt interlock module but that was cut out long ago, but I'm not positive on that. I don't want to power up the wiring right now as I've got more work to do and don't want to damage anything until I get some more cleanup done.

    Any chance someone knows what this wire does from the ignition switch? Is it a KO power that interrupts on start? (I may be able to use this for other uses if so)
    What triggers the Econo light to illuminate?

    Thanks, -Lee
     
    leeinphx, Jan 25, 2023
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  2. bmcdaniel

    bmcdaniel Senile Member

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    Low fuel economy light is activated by a vacuum switch at the engine. I never saw one on a Maverick but '70's Ford trucks had the switch mounted on the firewall with a hose going to the intake manifold.
    Ford truck and fuel economy used in the same sentence. LOL
     
    bmcdaniel, Jan 25, 2023
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  3. leeinphx

    leeinphx Member

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    Thanks. That's possible in that there are also two wires through the fire wall connector that do not show up either, so one of those may have gone to a vac switch. The econo light is wired with the other warning lights as they are all on a powered circuit then to ground through the switch to illuminate. It's confusing with the wire going to the ignition switch connector. I'll have to chase down some other vehicle wiring diagrams to see if that ign switch connection shows up somewhere. I guess ford may have put power to the circuit to keep the lamp from illuminating on start.
     
    leeinphx, Jan 25, 2023
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