I'm confused. The diagram you posted shows wire #35 going between the Alternator & Regulator, and my Master Wiring List says its White.
BUT: I looked at 2 '68 Mustangs that i have here, and the wire IS Orange.
I found 2 Orange wire listings: #172, going between a seatback relay to a seatback solenoid. (I have no idea what this is for.)
The second Orange wire I found listed, #807 is shown as the left door speaker wire.
Arlie, I will bring a copy of this wiring list to you in Lincoln. Its applicable to Mustangs 1965 thru 1973, and see what you think.
Neil