Garmin Wiring (24)

 24 hours (so far)

This is a project!  I've spent that last two weeks or so just stringing wires between all the Garmin components.  I'd guess that I'm probably about two-thirds done now.  It was sort of slow going at first because I had to figure out where to route all the wires, but once I had a path kind of laid out it was just a matter of adding more and more wires to the existing bundle, and connecting them to wherever they needed to go.

My goal for wire routing is to keep everything out of sight or at least totally out of the way of occupants and any moving objects (flight controls, etc.), and to avoid running wires through any holes that the whole bundle and connectors wouldn't fit through (so if I ever have to change anything I can pull the wires out without having to cut big chunks of the harness apart).

I am not counting the hours it took me to map out the Garmin wiring diagram for my system, but I have spent a lot of time on it!  I think I've been chipping away at figuring this all out since like April, and I'm still adjusting my diagram here and there as I install things and find issues with what I had planned.  Anyway here's the latest version of my Garmin diagram (you might have to click the image to enlarge it and then save it to zoom in... it's big):

I don't really have too many pictures of just running wires, but I'm not done yet so I'll try to capture everything once it's all installed.  However, here are a few tidbits I thought were worth taking pictures of:

First, I have two buttons on the stick: push-to-talk for the pilot, and an autopilot disconnect.  The PTT connects to the radio and the A/P disconnect connects to both autopilot servos.  Both are normally open and switch to ground.  Anyway I'm using the AeroConversions stick grip which has spots for two buttons, and I got the buttons from Aircraft Spruce.  I drilled a hole and installed a rubber grommet in the side of the steel tube part of the stick, and fished all the wires through there, and then soldered them to the buttons.  I ran all the wires to the right, and terminated the ground wires with a screw through one of the seat support ribs.  The other two wires went off to join the rest of the wire bundle towards the servos and radio.  Really the only tricky part was figuring out where to ziptie the wires to the stick in a way that they couldn't get stuck or wrapped around anything through the full range of motion!

I also shortened the stick by about 1.75" to clear my extended panel.

Black is PTT and red is A/P Disconnect

Next, I installed the Garmin outside air temp probe (GTP 59), just behind where I put the ADAHRS, which is what the probe is wired to.  This made for a short wire run!

This is all the wire I needed to connect the OAT probe.  It came with a 10' lead so that was just free wire!

OAT probe location.  The four screws just forward of it are the ADAHRS.

Finally, although I'm connecting just about every ground wire to the grounding block on the firewall, I found that it was pretty easy to ground certain momentary switches to the switch itself.  Here's a pushbutton I have on the panel that engages the autopilot when grounded.  Seems like the easiest way to do it if you have a ring terminal the same size as the switch body (this one is 1/4")!