Looking for wiring help

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  • Bob Nash
    Frequent Contributor
    • Oct 2004
    • 5

    Looking for wiring help

    I am trying to track down schematics of the wiring for the A4. I have seen a few versions published, but none seem to correspond to what I see on my boat, especially at the instrument panel. My 1970 vintage Pearson has a 3-instrument cluster and a push button for the starter in the cockpit, with the ignition key located in the cabin next to the companionway. I have never seen a schematic that takes into account the push button starter, which a lot of us probably have. When I see the proper colors of the wiring on schematics--including the useless diagrams in my original Universal owner's manual--I have to laugh: Pearson seemed to have three colors of wiring in the shop when my boat was built--red, black, and white. But that is less of a problem than trying to figure out what goes where and why (although to start out with, where is more important than why). I have also seen reference to in-line fuses being recommended at various points, but my boat has none. It would be great if the possible combinations and permutations could be gathered in one place.
  • Enigmalk2
    • Oct 2004
    • 4

    Wiring Diagram

    Bob.....I rewired my P-30 a few years ago and you are right .about the original wiring diagrams. However I am sure that I have a copy of the originals around somewhere.

    Instead of the original 7 circuits I now have 16. I find that this is much easier to work with than the fewer put in place by Pearson. There are several fuses mounted in the engine compartment, to the left on my boat, and they are for the shore power ( 120 v) circuit. I must strongly advise you to tear them out and replace them with circuit breakers.

    If you will send me your E.mail address, I will be happy to copy the original diagram I have to you .

    Lee K.


    • Administrator
      MMI Webmaster
      • Oct 2004
      • 2195


      If you are successful in finding them, may we post them here as well?



      • Don Moyer
        • Oct 2004
        • 2823


        Thank you! You have articulated (more succinctly than most) the frustration which stems from the fact that each boat builder seems to have chosen his own DC power distribution and color schemes. Add to this dilemma the fact that prior owners have frequently altered part of what their boat builder may have originally installed, and you can appreciate the plight of many of your colleagues - just in case misery really does love company.

        We'll keep our fingers crossed that Lee will be able to find his original schematic for your Pearson.

        In the meantime, and in case it is of any help to you, here is a link to the generic schematic of the basic DC Power Distribution that we handed out at our last Atomic 4 workshop.

        In your case, you'll have to add a wire from the "Batt" terminal of your ignition switch to one side of your push button starter switch. The other side of the starter switch will be connected to the "S" terminal on the starter solenoid.

        Best regards,

        Don Moyer


        • gddohn
          • Oct 2004
          • 2

          Pearsons idea of wireing was the shortest distance betwen two places is 3 different colored wires spliced together.


          • msauntry
            • May 2008
            • 507

            Rewire and who knows what you'll learn!

            On a whim, I decided to rewire my engine compartment. Things were working fine, but I had wires going everywhere and I didn't know what they were for. So in the interest of fixing what wasn't even broke, I tore into it. It'll take about a weekend to rewire if you go for it.

            I cleaned up the stack of leads on the IGN and pos. coil with some common buses. I also switched from a key and pushbutton start (similar to yours), to a 4-way keyed ignition switch. I put my blower on the ACC position which is a great improvement over my old setup of having to reach to the panel in the cabin below to flip it on and off when using the engine. The switch puts it all in one spot.

            I discovered my oil safety switch was being bypassed. I also had a lot of stuff coming off the R terminal on the starter solenoid. That was odd, because I noticed in my research here that Don recommends not using the R terminal. Mine was just acting like a common bus.

            Glad I fixed it, and it made my engine compartment much nicer. Educationally, I now know what each wire is doing!