Help ID wire under hood

[TheDude]

Hello, could use some help IDing a wire up front at the passenger side front corner. It's switched 12v and from the location and length of it, seems like it could be what should be used for the ignition or even connecting to the alternator. It's a two wire connector but only has the one wire. It's yellow with what looks like a faint faded red stripe. Appreciate any feedback,

Thanks

 

[midlife]

Normally, that is green/red. It's the lead to the alternator harness.

 

[TheDude]

Interesting, OK thanks. Now I'm wondering why it's not hooked to anything.

 

[Hemikiller]

Connects to the matching plug on the alternator harness. Location on the regulator plug varies betwen gage package and warning light cars. This is the warning light harness.

 

[TheDude]

Thanks. I'll have to dig around and see how the alternator is actually hooked up as it is working and not hooked to that wire.

 

[mrgmhale]

That wire being yellow and a hint of what might have been a red stripe is throwing me. Is that wire leading back into the main wiring loom under the hood? Below is a link to my Google Drive, where I have several schematics and related information for the 1973 Mustang charging system. I added the Wire Coloration chart showing what circuits correlate to certain wire color schemas. Hopefully you cake some sense of it. If your Mustang is a 1971 let me know, as there are some changes between 1971 and 1973 that "may" be relevant.

I also have more schematics beyond the charging system. I am not sure if it is reasonable to think that wire is somehow related to the charing system given its color schema. Unfortunately our 1973 Mustangs are both in Winter Hibernation at this time, so I can't just go out to them and look for a similar wire in the same area. Or, at least where I "think" the area is. Could you provide some more photos a little further away from the wiring harness the unknown wire is running into so I can get some perspective on where to look on our Mustangs? I may be able to get to them this coming weekend, perhaps even sooner with luck.

https://drive.google.com/drive/folders/1hy0R1V0PmNX8aLWbY_Z7D0oXENJa2Zeh?usp=drive_link