Accessory and Ignition switching.

Hello.

Just going through my plans for the wiring of my PMU24.

Now I was planning to have the PMU turn on with the accessories switch and of course it has to also stay on when you press start, that will of course cut power to the accessories wire and therefore turn off the PMU. Now the PMU24 uses terminal 7 +12V switch to turn on. So of course I could wire both the Acc wire and IGN wire to this input, however then the PMU will not know when Acc is on and IGN is not so I won't be able to setup my logic.

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Now I think the work around for this is to have both Acc and IGN wired to the +12V switch so that its on for Acc, Ign and Start key positions. And then also have Acc and IGN wires going each to an individual input pin, this will leave the PMU powered on but also let it know which position the key is in.

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Would someone be able to confirm if this is the correct way to wire it. Thanks for any advice.

I was missing something with this, with both ACC and IGN outputs joined together at pin 7, Acc would be backfed by ignition when the key is in the start position, now perhaps this won't matter because I don't actually need the power to ACC to be dropped at start like with the OEM setup, because as long as the PMU knows when it is in either position I can use logic to drop outputs I don't want running during crank.

Of course I also have the option the add a diode to each feed to pin 7.

Still need to know if my approach is suitable though.