+12V while cranking, where to tap in?

[beast02er]

So I am trying to get my megasquirt working and am going through a list of things to make sure it will start soon.

I need to make sure I am getting +12V while cranking, I have a suspicion that I might not be.

I found one post saying tap in to fuse 9, 10 or 11. And then I was looking at my wiring diagram and it confused me. So if I could get someone to give me a firm answer, then I would probably be better off.

Thanks,

Bryan

red73

[2002john]

If you pull fuse box out carefully, you should see big green wire that is on #10 fuse with buss bar to #9 and #11 that is +12v Switched with key at III drive position. There should extra tab for insulated quick disconnect wire terminal. That is where I would put fuse for +12v for higher current electronics. If lower current is all that is needed coil +12v is switched on at same time as above.

[snowflake]

i took some +12V from fuse #5 or #7, for some aftermarket instrument gauges.

either way it's not hard to find out which fuse has +12V.

Grab a test light and poke around,

Make sure the ignition is in the off position so that your not grabing battery voltage in the ingition on position, unless that's what you want.

Once you find which fuses have battery voltage at all times, take the fuse out and see which side the power is coming and going form, so you can plug into the system and still be fused.

I'm pretty sure, battery voltage at all times in the fuse box, is fed by an overlapped wire directly from the main battery cable that's on the starter terminal,

SO, in reality you could really tap off of the Altenator or the starter since their mainlined to the battery.

Or you could strech out a new wire right from the positive terminal and put an inline fuse in that.

Whatever suits your needs best

good luck

[2002john]

I think He's looking for switched +12v, for using megasquirt ohterwise it would be powered up all the time, or would need manual switch to turn on or off.

[beast02er]

Yeah, it is for Megasquirt (so I need +12V while cranking)

John, to see if I understood you correct. If I connect a wire to one of the open pins on the #11 fuse terminal, I should be good? Poking around in there I think I was on pin 12, which probably doesn't get +12V at cranking, and explains where power shut off during cranking...

Thanks,

Bryan

[2002john]

Connection should be made at same side as the big green wire that is jumped between #9,#10, and #11. The other side is fused, for other circuits. If you add circuit on non fused, then put your own fuse in you will be coming from battery via key switch in on position and not the start which is momentary for starter. The coil is wired at this point on key switch, it is not fused though. IF that does not help disconnect battery, battery should be disconneted anyway when doing any of these tasks, Turn key to on position, put multimeter on ohms, put one lead on plus terminal of battery cable and one where green wire is connected on bottom of fuse box you should read continuity, and when you switch key off it should be open no connection. If you meter with ringer it should be easier