Sorry guys, I did forget about this last summer. Life happened and more important things grabbed my attention. That being said, I will not be pursuing this any further. It's a non-issue for me and I'm not tearing apart my Z to figure it out.

I’m going through the Nav delete myself and thought I would contribute. To your original question, no, pins 26 and 27 aren’t present on the harness. That’s pretty much what I figured.

Here is a picture of the harness (before adding pin 6 & 7.) It’s from a 2017, so I think some of the wire colors may be different than earlier years.

Sorry to re awaken this thread, but has anyone figured out a solution for the defroster ? Interested to see if anyone has found the solution or if everyone just learnt to live without it.

I've been keeping an eye out for this too. With the plug diagrams, where were these from? Curious if there's a version which shows the additional missing wires.