how to read the codes on the wire diagram

[raj]

I am working on my tac and temp gauge i have a good service manual. My past is catching up with me, when i was younger putting in after market gauges who cared what wires were cut. Now i want the stock stuff i do not know how to decode the letters and numbers on the diagram. any suggestions. Thanks

[ntstlgl1970]

Here is an explanation of the color codes. These are from later model chryslers but the way the circuits are identified hasn't changed much (if at all) in decades