Tach & O2 Wideband power source.

Discussion in 'Sparky's corner' started by Quick Buick, Apr 6, 2021.

  1. Quick Buick

    Quick Buick Arlington Wa

    67 skylark instrument fuse = 4 amp fuse.

    Ive been using the instrument fuse to run power to my tach. old school super tach 2..
    Its the only source I can find to run the tach ignition on, Accessory off. Play radio no motor running..

    Would I be pulling to much power to run the AEM 30-300. To me it seams to be the best 12v source.

    I don't really under stand just what the instrument fuse protects..... The idiot lights or the speedometer, dashboard lights..

    Ive never over amped a fuse before unless really need. Would replacing the 4 with a 5 be pushing it?

    Could also a 30 amp relay if needed using the trigger off the 4 and source..
  2. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    There are plenty of fuses that are ignition on 12 volts. Any of them will do. Blower motor or radio fuse.
  3. Quick Buick

    Quick Buick Arlington Wa

    Radio and blower are On with the key in the ACC position..... I know you dont want your tach ON while the the motor is not running while listening to the stereo.
  4. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    The blower is operational in the Accessory position, but only if you have it switched on. Even if you wired the tachometer to a fuse that had power in Accessory, it wouldn't draw much at all without a signal. Not for nothing, but the instrument fuse has power all the time. It fuses the instrument panel lights. You can turn them on with the key off.
    Last edited: Apr 7, 2021
  5. Quick Buick

    Quick Buick Arlington Wa

    Problem solved........
    Since the under dash fuse panel is not working for the Tach & O2 WB... The way I want it too.... I'm powering both the from the + side of the coil.. The coil is not powered in the ACC position.

    FWIW I never removed the resistance wire from the engine harness... Im using the resistance wire to trigger a bosch 30 amp relay to provide 12 volts to power the Coil for the MSD electronic distributor.

    FWIW the instrument is for the idiot lights, fuel gauge maybe others not sure .... The Panel & ash tray lights works off the lights switch..
    Last edited: Apr 7, 2021

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