Always Hot Connection For Radio Install

[Captain Obvious]

So... I'm looking over the wiring diagram trying to figure out the cleanest way to get an always hot voltage line to my new radio install and I see these on the wiring diagram:

Anyone know what these connections are all about?

I went to the garage to see if they really exist, and they did (at least on my 77 they did). They are present but unused and are located above the passenger's right knee above the relay bracket. Lo-n-behold, one of them is hot at all times just like the diagram says it should be.

So what's the deal? Was that some option that I don't have? Was there a factory electric fan installed in some cars?

It's on the wiring diagrams for 76, 77 and 78. I don't have one for 75 so I don't know about that year.

[SteveJ]

I looked on the 75 wiring diagram. The wire off of the defroster fuse does not branch off for that circuit like the later 280Zs.

[Captain Obvious]

So what the heck is the "Cooling Fan Motor Sub-Harness? Nobody has ever noticed them before?

[Captain Obvious]

What did they call the heat soak reducing cooling fan that blew on the injectors on the 280ZX's?

I'm wondering if maybe they realized as far back as 76 that they might want to include something like that and put provisions if for the fan, but never used it until some time after 78? That's all I got.

[Captain Obvious]

Here's some pics of the connections to the mysterious sub-harness. These pics are from my 77:

Still no ideas?

[SteveJ]

I traced the blue wire some. That circuit goes to several places. It would take some digging to be sure, but now I'm thinking it's for some feature involving the air conditioning.