Wiring Question - Rear Fuse Box

[Tidybuoy]

My rear fuse box was re-wired (thanks Timmy-2) and now that I am installing, I also decided to replace all of the pins on the harness that plugs into the rear fuse box (this was due to me having a short and melting one of the wires - hence the need to rewire the fuse box).

My issue:
1) the original rear fuse box did not have a lower/center make pin - see photo, lower right section.
2) the female plug did have a wire that connects to this non-existent pin but I don't know what this originally went to.
3) Since I now have PMO with Electromotive Ignition, I don't think I need this wire. But, for curiosity purposes, I'm wondering what this was for.

Original Rear Fuse Box (before re-wiring) - no lower/center pin:


Connecting Female End - Wire Harness (had lower, center pin):


Diagram of '73 Fuse Panel (mine is a '74). Describes Pin "Elect Mag Cntl Valve Gy/W NA" - upper/lower reversed in photo:

[Tidybuoy]

And just to show off, here's the re-wired fuse box from Timmy 2:

[timmy2]

Deleted for CIS cars, but still in the through body harness for MFI cars.
Porsche had one harness for all vehicle options. They removed wires that weren't needed sometimes, other times they left them there! Sometimes they just left stuff disconnected and taped up.
You should see what the '73.5 rear fuse panel wiring looks like!
Has all MFI wiring plus the CIS stuff....
Gotta love the transition years.

[timmy2]

You need to buy/install a cover for the 3 rear fuses.

[Tidybuoy]

Somehow I knew you would know the answer

Since I am going to replace the plastic connector on the harness tonight (notice the plastic tab between the fat yellow wire and it's neighbor has broken off), I will also eliminate that gray/white wire. I always thought it was for a heater blower motor that I also don't have.

I'll add the plastic cover to my shopping list. Project will be finished this weekend