I just wired my radio in recently. So to confuse everyone this is what I found on my 1954 chevy 3100.
I tested the three positions on my ignition. With the key in the off position (center). One had power that was the one coming from the ammeter. The other two had no power made sense to me.
With the igntion on (Right)everything had power all three posts that made sense to. With the ignition turned to the left Only 2 posts had power the original from the ammeter and one of the other post. I asummed this postion is for accecesories this is the post I put my radio to My radio works with the key turned on to the right and left. I think its pretty simple.... my heater also works off the same terminal as the radio.
