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Thread: Wiring manual override switches.

  1. #1

    Default Wiring manual override switches.

    I have a question about wiring in a manual override switch for things such as a cooling fan or secondary fuel pump. I’m assuming that I should be using a diode on the output signal wire from the ECU to the signal input terminal on the relay. Then have the output wire from the switch go into the same signal input terminal on the relay. Then I will have no issues with my ECU correct? What amp diode should I use? Thank you.

  2. #2
    Join Date
    Dec 2009


    May God's grace bless you in the Lord Jesus Christ.

    '78 BRONCO: 508" stroker, TFS heads, 11:1 comp ratio, Dominator MPFI & DIS, cold air induction, Spal dual 12" fans/aluminum radiator, dual 3" exhaust/Magnaflow mufflers, Moroso vacuum pump, Accusump, engine oil & trans fluid coolers, 100HP progressive dry direct-port NOS, A/C, LenTech Strip Terminator wide-ratio AOD/2500 RPM converter, 3:1 Atlas II, modified Dana 44/60-lockers-4.10s, hydroboost/4-disc brakes, ram-assist/heim joint steering, Cage long radius arms, traction bars, 4" Skyjacker lift, 35" mud tires

  3. #3


    So I can splice my ECU output and my switch output together right after the diode on the ECU output? Then they can go together directly to the relay? Sorry for the stupid questions, I just don’t want to damage my Dominator ECU. Thanks.

  4. #4
    Join Date
    Nov 2013
    Chicago IL


    If you have enough Inputs, you can just take your override switches into the ECU.
    Then have the ECU trigger the fan & fuel pumps by either the switch or sensors.

    Last edited by S2H; 01-17-2018 at 10:50 PM.
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