To Truckolet and to Bill. You are asking questions by looking at the diagram and trying to make sense of it and also wire up someone's truck. So I will try again.
They may be showing two ways to wire on the same diagram. I can not defend the diagram. I do know how to wire various components used together.
If you want to know how to wire a SPECIFIC set of components. TELL ME what they are.
Some solenoids have an "R" terminal. Some early one's DID NOT. wiring will be different.
There are several iterations of ignition switches. Need to see a pic of the terminals or describe the terminals.
After I know what you or friend has EXACLTY, we can wire it.... and then explain wires you see on the diagram after that. It will then make total sense.
Other than trying to show more than one system on one diagram. I don't see anything "wrong" with the diagram.
There is no such thing as the items on my list "not applying". It is simply a list of possible scenarios which need to be concidered when discussing the ignition wiring and the diagram. I call then variables.
During the time Chevy came with 12V and V8 at the same time, the so called electrical engineers where, themselves, mixed up and kept changing things in TF years.
From what the documents say. Forward control, 3700, 3900, and automatic trans had 3 position switches. Solenoid.
All others had 2 position by "foot start" or "depress starter" or "foot pedal" or "push button". All terms used 55.2-59.
In 1959 they say V8 had solenoid starter. One of the original GM switches is called the "V8 Switch" by some bolters. (spring loaded, IGN 1, IGN 2, BAT, START, ACC)
A specific TF truck or any trucks starting system is usually not totally original anymore due to some switches not available, changes made to starters and overall ignition by PO. So then you adapt to your components while maintaining point protection, bypass and using what switch you have. I.E. Spring loaded, 3 pos, 2 pos, pedal, push button.
