So, I looked at my original wiring diagram and the 1964 version that someone posted on here. The 1964 version is more accurate, but still not correct.

The Ford diagram shows two Red/Blue wires coming from the Ignition Switch Harness (connector)--one large and one small. However, the diagram shows one from the B terminal and one from the S terminal. But, when I run a test light to it, they both light up when I have the S terminal (spade wire jumper) connected. Neither one of them light up (that I could tell) when using the jumper connected to the B terminal.

Can anyone explain this to me?

Thanks,
Paul

 

Little foggy remembering when I wired my ignition and haven't seeen the diagram, so I don't know exactly which terminals you are talking about. But I do remember that in the stock Ford ignition wiring the coil gets 12V when the starter relay is clicked, but drops to 6V through the ballast resistor once the engine is running. Don't know if that helps or not.

 

65 Hot is correct about when the truck is starting verse started.

GENERATOR SCHEMATIC is as follows: Power (12v) originates at the battery side post of the solinoid at the red/blue wire #1 with a 1/4 inch ring terminal, you called the fat wire. It then travels through #1 to the ignition switch "B" terminal. When the key is switched on, it then travels out the "S" terminal of the ignition switch through the smaller red/blue wire #2 to the "S" terminal of the solinoid. This engergizes the solinoid to pull the contacts down and send the full amperage of the battery directly to the starter and ignition coil power out the solinoid "I" terminal.

While the key is in the starting position, both "B" and "S" of the ignition switch with allow power to go through. The primary power on the ignition switch "C" to the coil is not sending any voltage during the starting process. That is why you have the "I" terminal of the starter solinoid. It routes a full 12v to the ignition coil to increase the strength of the spark to start it faster. Between Starting and Running there is no power going to the coil for a split second while the ignition switch contacts are changing. (You may run into a condition where the engine starts but dies as soon as you let off the key. Remember this point, the coil is not getting power from the ignition switch in the run position.)

In reality what you are doing when you see both "B" & "S" hot with a jumper is powering the little red/blue from both ends of it.

If you want to always remember what wires go where on the ignition switch, notice the leters of the terminals. B, S, C, and A? B = battery. S = start. C = coil. A = accessory. With that said, if you want your radio to come on in the keep set to ACC wire it to the "A" post.

 

Double post...see the next one.

 

There are two possible ignition switches found on these trucks. They are not the same.

1961/66: The original switch has three terminals: C3AZ11572A (Motorcraft SW353)

In 1967, Ford obsoleted the three terminal switch, replaced it with a four terminal switch (C7UZ11572A / Motorcraft SW583) for use as a Service Part replacement..

People have been confused ever since Ford went to that four terminal switch...because it does not match the original wiring schematic.

There is no ballast resistors per se on these trucks...what it there...is this:

COLF12250A .. Resistor WIRE-Ignition Coil (Motorcraft DY37) / 61.49" long / Color coded Pink / 1.30-1.40 ohms resistance / #20 gauge wire.

 

If I have the harness removed and a jumper installed, both RED/BLUE wires will light with a jumper in the S terminal. However, neither/none light when the jumper is in the B terminal. The only wire that lights up the test light with a jumper in t he B terminal is a fat (12 gauge) YELLOW wire.

I'm still confused. The YELLOW wire and the fact that none of the RED/BLUE wires lighting with a B jumper has me stumped.

What do you think regarding THAT?

Thanks,
Paul

 

"S" terminal on the ignition switch or solinoid?

 

The yellow wire is for the power generation system. Both it and the Red/blue wires go to the "B" of the ignition switch. Both the Yellow and 12 gauge red/blue wires go to the battery side of the solinoid. Look at .gif 8 on the TOCMP site for the 64 F100 you will see what I mean.

With the EZ wiring job you are doing you could forgo the extra power lead to the ignition switch and just route a single red/blue wire from the "S" terminal of the ignition switch to the solinoid.

 

Mark...could you write me at lostarkitekt at Gail? I would like to explain this better. Maybe I could call you.

Thanks,
Paul

 

Mark,

I sent that last reply from my BlackBerry, so I guess I left off the "M" in Gmail. Anyway, my email is lostarkitekt at gmail. Hope this gets you as I'm trying to finish the wiring tomorrow. Anyway, the point was that NONE of the RED/BLUE wires seem to be connected (internally) to the B terminal of the ignition switch harness. They are both hooked to the S terminal...at least that is what my jumper wire keeps telling me.

Paul