The Magic Bus

After getting over my mishap from yesterday, I started early to enjoy the cooler temperatures of this weekend. I prepared the APDC switch for the eventual cutting of the connected wires and the add-on of a Molex connector.

I didn't cut or install it yet as I want to move the switch from its intended position on the center panel to above the Skyview display. I think it will be easier to get at than trying to hit a button hidden between two large levers. The intended spot of the switch is much better used for a fuel pump switch that will only rarely be used and never in flight.

Anyway, more than marking the wires wasn't really appropriate right now, so I moved on to inserting the wires of the second conversion harness. This is the bundle of WH-00036 and that one doesn't end at the wing split-off but goes all the way to the back where the ADAHRS will sit. These wires are obviously the power supply and the magic Skyview bus.
Unfortunately, this wires bundle cannot easily be installed beyond the point where the two new snap bushings were installed. As it has to go through the tunnel those retainers had to get loosened up a bit.

Just enough so the bundle could slide through. I taped the bundle on the tip and then every foot or so, just to keep it tight while pushing it through the openings.
Here it's coming through.

That went all well until it reached the main bulkhead, right behind the flap handle. This is the worst bushing of all of them. It's already very tightly filled with wires and it's in such a bad location that you cannot get a hand or two fingers to it to help the bundle through.

With the help of some big HF tweezers and a pair of needle nose pliers I got it pushed in far enough so I could grab it from the other side reaching through the service holes and pull it through. After that point it's fairly easy.

I pulled the bundle through so I could focus on the aft part of the job. All the following bushings are fairly easy to access and not too tightly filled. By the way, I'm really glad I removed the obsolete bundle that connected the magnetometer before. These extra 4 wires would have made this job much harder.
When you get to the last bushing, it gets a bit tricky again. It's tightly filled and hard to access again. This time, the servo for the ailerons is blocking your hand from pulling the wire through from the rear. At least until you get about 2-3 inches pushed through.

I finally prevailed - with the help of the tweezers again - and pulled the rest of the wire through to get it tightened up. Failure!

Look closely and you'll see that the bundle went on the upper side of the fuel line and not below it like the rest. So I pulled it out again and did it correct the second time. It was easier as I was still warm using the tweezers.

Here you see the wire pulled through, along with the main tools to finished the job.
One of the good things of crawling so deeply into the guts of the airplane is that you get to see things from an unusual angle. So unusual that you might to see stuff that surprises you. Like this one here:

No, not the tree! The back support bar! Look closely and you'll find a whole bunch of rivets missing. That explains why this piece always felt a little soft when used as a weight support for my body getting in and out of the boat.
I flipped the instructions back to where this was supposed to get done.

Also, I noticed that Dave put the piece with the holes in covering the flange. I couldn't determine that precisely from the instructions and put it in how it fit better. I think this might be wrong, but I'm not sure if it really makes a great difference. Depends on what sideways forces this part would have to hold.
It could get fixed by drilling out a bunch of rivets but I'm not convinced that I'm going to do that yet.

Moving back to WHB-00036 which just got installed. I found that one wire RED/WHT had to get isolated and pulled back to the main bulkhead tunnel. This wire is supposed to get routed along the ELT phone wire and probably is some sort of ELT hook-up or future extension.

Once it's in the gear leg tunnel it gets routed upwards through the bulkhead and then has to travel through the wire hose to the right side. Good I left my threads in place, so pulling the wire through the hose was really easy. Here you see the wire connected to the rope with some blue tape.

Guiding the wire into the hose until it doesn't snag on any edges anymore and then just pulling it through until it shows up on the other side.

This wire got a little splice crimped on but got not connected to anything yet, so it just waits there for final cleanup for now. Back to the WH-00036 harness. Those bus and power supply wires had to get connected to the D-SUB 9 plug that we had relieved from its connections the other day.

That didn't take long at all. Then on to the only wires left back there. The ones from the OAT probe. The shielding and a red wire get cut off and covered with heat shrink tube and the two wires left get crimped on to WH-00008, which is the little plug with the short wires coming out of it.

That was it for WH-00036. Back to the wires I had left from WH-00026. They got routed to the wing split-off point but then I didn't follow through with them. One of them was supposed to replace the power supply to the 12V power outlet. This one is called P350 and it was kind of hard to find and isolate. It's just the shortest white wire on that harness that's not connected to anything. I verified it by tracing the wire back to the plug, its pin and checking it with an Ohmmeter. Then I labeled it, crimped on the spade connector, hooked it up and removed the obsolete previous wire that went through the grommet to the front of the fire wall, awaiting an inline fuse holder and a hook-up to the battery that will never happen now.

Only 4 wires left. Two of them were easy. They are uniquely colored in ORN/BLK and run to each side of the plane and get tie-wrapped to the headset plugs and their ends get heat shrinked. I found that odd that they don't connect to anything but get assigned to a hook-up place close to the headsets, so I studied the electric diagram again. I had a hunch .... and I was right. These two wires are carrying 12V power supply to the headset plug areas. They are fused with 5A and they are going to pin 30 on the Options plug which is called Audio Power. So to power your Noise Canceling Headset from your ship's power supply, just identify the necessary plug and hook it up to those wires and done. How's that? I love it!

Also notice the two white thicker wires that leave the seat pan area in the picture to the left. They cost me some time digging in the diagrams again. According to the plans I now know that they are supposed to be YEL/RED which they are clearly not. They have little tags on them at each end that identify them as WH-L456 and -L458. To make a long story short, they are the nav light power supplies which should get routed to each wing electrical connector to get hooked up in the retrofit action that will allow you to choose between using the strobes and nav lights together or just the nav light without the strobes.
I routed them but as I cannot get to the left side at this time, I didn't do anything else.

That concluded a successful day in the shop. I really appreciate that Van's has released the electrical diagrams! I can read them and it makes all the difference between guessing and knowing. I prefer the latter, no doubt!
Tomorrow I will try to continue in section 31 and finish more wiring work from the previous D-180 layout. Then I might be able to close up those old plugs and finish the retrofit work in the panel area.