Here's the drawing from before.
The orange lines in the start switch illustrate the connection during start.
The orange arrows represent flow.
Flowing electrons is current. Flow only happens when a circuit has a return path.
Voltage is potential to flow, but its not flow.
Lets look at this diagram again, but with the key off.
Using a voltmeter, measure from the battery positive to ground. It should be around 12.5 Volts.
If you move the red probe to any point along the wires connected to Battery positive, the voltage should be the same.
For example, the alternator feed will be 12.5 V at the bulkhead and at the alternator's output stud, labelled BATT.
So will the ammeter connections. But there is no current flowing through it , so it shows 0 amps.
Lets go again to key in Start, the situation you need to diagnose.
The connections made in the start position should provide battery power through circuit S (and we know it does because the relary closes and starter gets power)
and it should provide battery power to the J2B and J3 ignition wires to the coil.
I'm showing only 12 Voltsin the diagram because a starter will often draw down the battery voltage. You may find its 11 somthing. But it should be the same everywhere until it goes through some equipment like the relay, or a bad connection.
