Your missing my point.
The board is what it is. It just made me wonder what has been changed.
The ammeter may not be an ammeter - that's what I was getting at.
It should look like the one I posted.
Another view
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If the fuel gage is suspect, then take it out and look at it. It can be checked out - there's a number of threads where we've done this - and also factory tech tips.
Follow your nose and eyes. You see a place where the ammeter stud contacted something - well thats the battery connecting and shorting.
The electrical diagram is just like a road map. We don't take every road, we just follow the ones we're interested in. The electrons follow a path connecting them from positive to the negative.