The blue/black wire from 58a of the light switch enters the ignition switch harness/bundle and goes directly through it to the ashtray lamp. No interruptions or connections to anything else.
Note:
(There may be a jumper to a resistor on some configurations for the hazard light switch depending on the year, at the light switch connector end.)

Then, the blue/black power wire goes from the ashtray lamp to the hvac lamps. All wired in parallel.

Grounds run to each lamp and to a ground terminal.

I’m basing my description on earlier cars, main reason I don’t build any of the Carrera body harnesses is they changed a ton of stuff.
Kroon has photos of two different ignition harnesses on his site.
They look different than earlier ones.

So as a first step in sorting this out decided to install the inline fuse provided by Engelbert. Install was straightforward, but noticed one of the two wires (blue/black) connected to 58a at the switch had also been damaged. I wrapped it in electrical tape, but the instrument and parking lights never came back online. It's not the fuse; even when both wires at 58a are directly reconnected to the switch, I don't get instrument or parking lights. If I hadn't been back there to install the fuse, I may have found this problem the hard way.

At this point I guess it makes sense to just replace the ignition wiring harness. Is this the one I need or is there one that's specific to the 930? Is there a US supplier for this?

https://www.kroonwireharnesses.com/porsche-911-1985/ignition-switch-harness-for-porsche-911-1985-1989-artno-91161201134

Thanks

Take a look at restoration Design

https://www.restoration-design.com/store/product/RD-911.612.011.32

Thanks, Rothaus. Looks like that one is good through '84, mine is an '87. Not sure if there's a difference. The patient is an '87 930. Sorry for not making that clear.

So it looks like the 87-89 ignition harness is the same for the 911/930. Kroon has both the ignition harness and the harness for the heater panel lights. Including international shipping the price comes to nearly 400 euros, but that may actually be the best option.

It doesn't look like Restoration Design offers the later harness, unfortunately. Their prices are a lot more reasonable. Any other alternatives to Kroon?

So just got the two harnesses from Kroon. The ignition harness is complete and looks pretty good, but is missing the "detailed instructions" that were supposed to come with it.

The heater control lighting harness is missing the both sockets and the housing for the ashtray light, though they're both pictured in their listing for part number 911 612 172 00. They actually have a separate listing for the same harness but without the sockets for 6 Euros less, so not sure if this was a mistake or deliberately misleading. I've contacted them, so we'll see.

The ignition harness itself has two sockets as well. Those weren't missing. What are they for?

Thanks!

Excellent customer service from Kroon. Turns out they sent the wrong product by mistake. They apologized and immediately shipped out the complete harness. No BS. It is scheduled to arrive Monday.

The ignition harness itself is very nicely put together. So far I've been able to restore my instrument, brake and marker lights. The only minor issues with their product are that the main socket does not install flush with the ignition switch and the plastic terminal cover on the gray wire appears to be too small to fit the corresponding connector. Otherwise it's similar to the original wiring and includes everything.

Could someone please show me where the two lights and the rest of the wires go? So far I've hooked up the four wires that connect to the light switch.