1974 Targa mystery wire

[74Targa911]

Hello to all. I am in the process of making my 1974 Targa roadworthy again. I purchased the car with the engine already removed so I did not have the luxury of disconnecting everything to know where it goes when reconnecting. I have a pretty good idea where everything went except for one wire.

In the engine bay on the drivers side there is a group of three wires that split off from the main harness right by the fuel filter and accumulator. Two of the wires are brown earth wires that go to the body. The third wire is gray and I’m not exactly sure where it goes. Judging by the length of it, I would say that it goes to the grounding spade terminal on the permatune box, but I’m hesitant to just hook something up to the ignition unit without knowing what it does.

Any idea where this wire goes? Attached is a pic.

[gerakroo]

This wire ( i think it must be grey-white ?) goes to the cold start valve.

[FL911SC]

Just a guess, but would it be for the rear window defrost?
I have a "79 in which the rear window just reinstalled. The installer declared the terminals on the glass unfit so he didn't pull any of the wires up, so there were a couple of wires left over. Some of these were longer than I would have expected, however none of them was solid grey.
Based on the length and location, rear window defrost is my guess.

Good luck!!
Keith P.