Four way brake union

Electrical and Ignition

  1. Mr woodbeard

    Mr woodbeard Member

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    Hi all hopefully someone can help me iam new to this. Where my four way brake union is there is a wire coming from it which at some time has came loose and I have no idea where it reconnects to I’ve added a picture if that’s any help. It obviously going somewhere in the block where all the other wire go but which one . Cheers Mr woodbeard

    7D8E35A4-235A-4013-90BF-E643646A38E2.jpeg
     
  2. 67Dart273

    67Dart273 FABO Gold Member FABO Gold Member

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    That is the brake pressure warning switch. It is in parallel with the parking brake switch, and when either is grounded it activates the warning lamp on the dash. It should not be difficult to find, it has a plastic connector that fits over the stud on the switch

    What year/ make / model are we working on?

    You can download free factory service manuals and 3rd party aftermarket wiring diagrams, at MyMopar
     
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    • Mr woodbeard

      Mr woodbeard Member

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      Hey it’s a 1971 dodge d100 v8 318
       
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      • Ironracer

        Ironracer Gearhead

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        I had a 74 d200 4 door. What a ripper!
         
      • Dana67Dart

        Dana67Dart The parts you don't add don't cause you no trouble FABO Gold Member

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        Pictures are worth a 1000 words, jeep them coming. Also important is year and vehical being worked on and any modifications done and what was the last thing done to the car before the problem started.

        The post the wire goes on to should look something like this
        Screenshot_20210815-144826.png
         
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        • Mr woodbeard

          Mr woodbeard Member

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          Yes this one shift just have to remember early braking as it’s still on drum brakes
           
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          • Mr woodbeard

            Mr woodbeard Member

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            Hi yes that’s on the chassis with the wire in it it’s where the other end of the wire is connected to I can’t find
             
          • Demonracer

            Demonracer 71 Demon 00 Ram 16 Chrysler 300S 05 Caravan FABO Gold Member

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            Find a FSM with wiring diagrams.
             
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            • Murray

              Murray FABO Gold Member FABO Gold Member

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              There is a safety switch built in to that distribution bock. It senses unevenness in hydraulic pressure between the front and rear brakes if the M/C fails or a failure in the lines. Then by way of that switch it activates a light on your dash to notify you.
               
            • Dana67Dart

              Dana67Dart The parts you don't add don't cause you no trouble FABO Gold Member

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              Most likely the bulkhead connector.

              As stated get a wiring diagram and trace it out.
               
            • Mr woodbeard

              Mr woodbeard Member

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              Thank you ill take a look
               
            • 67Dart273

              67Dart273 FABO Gold Member FABO Gold Member

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              Especially with a pickup, and some of the places some of them go, LOL, it's possible a branch/ stick hooked the wire and jerked it clear out of there or some such, or that a previous owner saw it dangling, could not figure out what it was, and just cut it off

              I do not have documentation on the trucks. Only other suggestion is to "spy" a similar truck of that similar generation and get the guy (or gal!!) to open up the hood for you
               
            • Mr woodbeard

              Mr woodbeard Member

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              Thank you for your advice I’ll take a look and keep you updated
               
            • Dartswinger70

              Dartswinger70 Catch a wave youll be sittin on top of the world

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              silly question I know you guys are talking trucks but does anyone know where the parking brake switch splices into the harness on a 1970 A body ralley dash in a Dart Swinger? I have a parking brake handle with a wire coming off the switch and no wire in sight from the harness to connect to. I have visually traced the black wire from the brake block, to the bulkhead connector then up to the dash, it splices off to the round connector to the printed circuit, then continues on to the fuse panel ( I think... I did do this visually LOL!) and there is no copper showing anywhere where the wire may have once been connected in the immediate area of the parking brake handle..
               
            • 67Dart273

              67Dart273 FABO Gold Member FABO Gold Member

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              It would not go to the fuse panel. The wire "you thought" went there is what you want. Those switches GROUND the brake warning lamp and the lamp has 12V on it on the other side from the key
               
            • Dartswinger70

              Dartswinger70 Catch a wave youll be sittin on top of the world

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              So, could I splice into that black wire on the interior side at the bulkhead connector? or should I be splicing in up near the dash connector. Or does it even matter. I was going to stick the copper end of the wire from the parking brake lever switch in at the bulkhead connector and see if the lamp would come on when I pulled the handle.
               
            • Mr woodbeard

              Mr woodbeard Member

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            • Mr woodbeard

              Mr woodbeard Member

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              Cheers I’ll take a look
               
            • Dartswinger70

              Dartswinger70 Catch a wave youll be sittin on top of the world

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              I appreciate it. it amazes me how may electrical issues I have with this thing going back together although I dont remember the brake light ever working LOL!

              UPDATE so I took a back probe wire with the wire from the parking brake lever switch, stuck it in the interior side of the bulkhead connector, I pulled the handle and I have a brake light in the dash. i am thinking I can splice into that anywhere. Its a matter of how it routes under the dash. I dont want anything hanging down etc. and I have the wiper linkage and clutch pedal etc.
               
              Last edited: Oct 14, 2021 at 6:13 PM
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