finding and tracing open circuit | Ford Escort Owners Association (FEOA)
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finding and tracing open circuit

Discussion in '2nd Gen 1991-1996 1.9L SOHC' started by juggalo, Jan 10, 2012.

  1. juggalo

    juggalo New Member

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    well i finally have been checking my wires to the ignition switch. the black and white wire which go to the cigar and radio fuses showed a lot of resistance. so did the white wire going to the chime module, wherever that is.

    so i unplugged the fuses and found one side to both connectors and the b/w with to the i/s having no resistance. i checked the other side of the connectors for the fuses and and to the ground which the radio fuse connector had more resistance than the cigar fuse connector. they both have resistance where other fuses do not. all i can see is the yellow wire from the cigar side which has the resistance but i can see where it leads to. the green connector on the bottom of the interior fuse pannel also has resistance at the yellow wire but so do both of those fuse connectors with it unplugged.

    i hate wiring. i'm so confused trying to find my problem. what r ur thoughts?
  2. Intuit

    Intuit FEOA Member

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    Had typed out a detailed reply the day you posted, only to have the server connection drop for whatever reason. (Grrrr.)

    Fellas, the back-story begins here:
    https://www.feoa.net/modules.php?name=Fo ... 709#687709

    It looks like the ignition switch selectively grounds these pins. The diagram has that black wire going off to the main fuse. So the switch selectively grounds pins through the main fuse.

    We need a diagram that includes the ignition relay. Has this relay ever been modified or replaced ? Is there some possibility that, somehow that relay is allowing current to be dumped off to the ignition switch ?

    You will see high resistance measuring through any device (except switches) to ground. (normal) If measuring just from harness-pin to harness-pin, high resistance could just be the harness blade connectors. High resistance through the wires themselves, could be evidence that they were subjected to high load. Once you eliminate bad connectors and singed wires, see whether the ignition/tumbler still gets hot.

    Black/White wire is for the ACC position. But isn't it the RUN and START positions that fail ? Or does the ignition switch ground BOTH the ACC and RUN pins; totaling three pins instead of just the two for RUN ?

    I'd want to use an amp meter as described before, putting it in series, starting with the ACC (Black/White) pin. You could generate load by running devices on the circuit while monitoring readings; see whether an over-current condition exists. Maximum load is determined by the highest/thinnest wire gauge that is used. The VesTest link has info on what load capacities are per gauge of wire.

    We have the wiring diagram for the RUN position's Black/Red pin, but not it's Blue pin. (Blue pin is labeled Dark-Blue in Haynes BTW) We also could use the diagram for the Black/White pin. The Blower Motor, Rear Defrost (30A Heater fuse) are on that Black/Red pin. Wipers are also on that pin.

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