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That is a nice, compact schematic. But, if you need more detail I suggest going to Forel Publications and downloading their Colorized Wiring Schematic(s). I use the plural (s) in the preceding sentence because the 1971 schematic (and earlier years) are not nearly as good as 1972, and especially 1973 wiring schematics. The price for the PDF schematics is really quite low. I would get one for 71, 72, and 73 just to make certain your bases are covered. The 71 version may be all you need, but the layouts in 72 and 73 are increasingly superior o the 71 format.
There are some differences in the schematics from 71, 72 and 73. But, they are relatively minor. An example is that the Throttle Position Solenoid (TPS) was not in the 1971 Mustangs, it began to show up in 1972, and Circuit 640 was tapped into and sent into the engine compartment to provide switched power to the TPS.
Another example is the 1973 Electric choke being powered by the Alternator Stator terminal, Circuit 4. That is not present in 1972, and I am pretty sure it is not in the 1972 model either.
There may be a few other differences, but the rich content of 72, and especially 73 schematics I am certain provide useful to you with your 71 Mustang.
https://www.forelpublishing.com/clickbank/index.html