Wiring Help

Discussion in 'Fox 5.0 Mustang Tech' started by rustyruststang5, Feb 11, 2014.

  1. need to know what exact year engine harness I have. it has mass air, it has one black relay by the mass air. it has one brown connection by the obd1 port. what else is needed to know what year it came out of? and if any one knows what those two components are in my last two pics that would be helpful

    Attached Files:

  2. The description fits an 89 or 91-early 92 5.0 Mustang Mass Air harness.

    Copied From bbunt302

    Just for reference, here's a list of all the compatible years:

    89 harness should work for 86-89 as long as you're using mass air. Single relay under the hood for A/C
    90 harness will only work in a 90. (B/c of air bags and dual dash connectors)
    91 through early 92 harnesses should be compatible (single dash connector, fuel pump relay under driver's seat)
    Late 92 through 93 harnesses should be compatible (single dash connector, fuel pump relay under the hood) Two relays, one for A/C the other for fuel pump

    Check the wire color for the pin 46 signal ground to be sure...

    Diagram courtesy of Tmoss & Stang&2birds

    Complete computer, actuator & sensor wiring diagram for 91-93 Mass Air Mustangs

    Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
  3. mine is grey/red at wire 46. I know my interior harness I have came out of 91 but I didn't see the fuel pump relay on it. granted the relay could of been pulled out. so since mine looks to be a 88-91 harness will it work with my 91 interior harness?
  4. and do you have a diagram of all the different o2 sensor wiring harnesses
  5. It should work OK.

    I don't have any easy to read O2 sensor wiring harness diagrams.
    Here is what I do have...
    O2 Sensor harness interchange and modification

    Originally Posted by 302EFI

    Revised 16-Oct-2011 to add O2 sensor harness warnings
    The wires for the 02's and low oil did not change throughout the years, they are all in the same place.
    The main ones you need to worry about are (on the harness end (ECU) that plugs into the 02 plug) is:
    \- 1. Lightblue / yellow
    - 2. White / Purple
    - 3. Purple / Yellow
    The White/Purple & Purple/Yellow gets looped for a automatic ECU
    The Purple/Yellow & Lightblue/Yellow for a manual ECU

    See http://forums.corral.net/forums/gen...manual-auto-differences-year-differences.html for more O2 sensor wiring harness info

    Basic premise to use with transmission swaps:
    Only run a 5 speed trans O2 harness with an A9L. Do not run an Auto O2 sensor harness with an A9L. Doing so will damage the computer’s internal signal ground.
    Only run an Auto trans O2 sensor harness with an A9P in a car that has an Auto trans. Using a 5 speed trans O2 sensor harness with an Auto trans will cause no crank problems.
    See http://www.stangnet.com/mustang-forums/749974-computer-issue.html#post7490537 for Joel5.0’s fix to the computer internal signal ground.

    90 model year harness only works with 90 model cars without inspection/rework.
    The 4 cylinder O2 harness uses 4 wire O2 sensors. It probably won’t work correctly without modifying it.

    The green/yellow wire is the 12 volts for the O2 sensor heater, the black/gray wire is the signal & heater power ground, other wire is the O2 sensor output. The sensor wiring is Teflon insulated to survive the high heat around the exhaust system. Use regular insulated wire on the O2 sensors and the heat from the exhaust will melt or damage the wire's insulation.

    The numbers on the sensor body match the numbers on the sensor socket. That shows you what wires are the heater, ground and sensor outputs.

    60 is the sensor and heater ground. It terminates up in the engine fuel injector harness with an orange wire that bolts to either the back of the cylinder head, intake manifold or car body. Make sure this is grounded if you want the O2 sensors to work correctly.

    90 (dark brown/lt green)& 94 (dark green/Purple) are the O2 sensor outputs.

    687 is the 12 volt O2 sensor heater power that connects to a fuse link in the wiring harness.

    The diagram for the O2 sensor harness is below:
    Diagram courtesy of Tmoss & Stang&2birds


    See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/ Everyone should bookmark this site.

    Ignition switch wiring

    Fuel, alternator, A/C and ignition wiring

    Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs

    Complete computer, actuator & sensor wiring diagram for 91-93 Mass Air Mustangs

    Vacuum diagram 89-93 Mustangs

    HVAC vacuum diagram

    TFI module differences & pinout

    Fuse box layout
  6. Thanks your always a big help