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Thread: Auxiliary harnesses?

  1. #1

    Default Auxiliary harnesses?

    I will be buying Dominator soon and was wondering what some of the auxiliary harnesses were for, and what would be good to purchase right away?

  2. #2
    Join Date
    Dec 2009


    Most people find this document very helpful: (Holley HP & Dominator EFI Component Selection Guide)

    Dominator Auxiliary Harnesses:
    If this is a dual WBO2 sensor application, the Holley 558-401 J2A Auxiliary Harness also
    has 23 additional Inputs of all types (no Outputs), Sensor +5V power & Sensor Ground. (Holley EFI Wiring Manual - J2A Pin-Out/Inputs, Pages 7 & 27)
    Of course, the Dominator ECU has custom I/O on every ECU connector, but you can start with this:

    To connect up to 4 Inputs & Outputs to the EFI Main Harness, use I/O Auxiliary Harness 558-400.
    Eight Wire I/O Auxiliary Harness Connector Pin-Out (also in the Holley EFI Wiring Manual - LINK):
    Pin A...A12...White/Blue (Input #1) F,5,2,T,H,G
    Pin B...A3....White/Red (Input #2) F,5,2,T,H,G
    Pin C...A13...White/Black (Input #3) F,5,G
    Pin D...A4....White/Green (Input #4) F,5,G
    Pin E...B12...Gray/Yellow (Output #1) H,P+
    Pin F...B11...Gray/Red (Output #2) H,P+
    Pin G...B10...Gray/Black (Output #3) G,P−
    Pin H...B3....Gray/Green (Output #4) G,P− (Holley 558-400 I/O Auxiliary Harness Instructions)

    The 558-400 I/O Auxiliary Harness is 20 feet long.
    It's "plug & play" into the main harness, and an easy way to connect common things like an electric cooling fan (Link).
    This I/O Auxiliary Harness isn't required for the optional oil & fuel pressure transducers, which are also "plug & play" into the main harness.
    The oil & fuel pressure transducers are used for Data Monitoring, Data Logging and setup Outputs based on oil & fuel pressure.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

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