Garmin G3X Avionics Schematic Drawing

Wowza, putting together these documents was a heavy lift. Rough guess is 150 hours of research, drawing, and validation. Initially my plan had been to hire Stein Air to draw my schematics but Covid-19 gave me the time to do the research and work myself, and in the process save $1,000. You need to be very technically proficient to take this on, if that isn’t you go the safe route and work with Stein they are great people and will give you all the support that you will need.

CAUTION: NO CLAIMS ARE MADE TO THE INFORMATION BELOW! Do you own research, testing, and validation. This is put out there just for informational purposes and to give you a head start.

MAJOR THANK YOU: I started this process and had a rough schematic drawn up before stumbling on Leo Knowlden’s post on VAF. He put together a impressive amount of information about his “Electrical System Design and Build.” I used Leo’s schematics to cross check mine and to make improvements, like finding a number of important wires I had missed. Our systems have a number of differences and I drew my own schematics but the work he put together and shared was a huge boost for me. Thank you Leo!

August 19, 2020 update
Another MAJOR THANK YOU: Steve (Longez on VAF) pointed out a mistake on the MAPMX wiring to the G5 and that the second mangetometer would be problematic. I have updated the block diagram and schematic documents (links below are updated with these corrections).

And with that here are the design documents that I have put together:
N241VP Garmin G3X Avionics Block Diagram
N241VP Garmin G3X Avionics Schematics
N241VP Electrical Schematic

As validation there was information spread over many Garmin documents and searching through hundreds of pages was a major pain. So I generated a couple of documents that consolidate the Garmin manuals to only the applicable pages.
Garmin Wiring Diagrams
Garmin Connector Pinouts


  • Richard Horan April 20, 2020 at 11:38 pm

    Nice layout, have been struggling to design a G5 into the Aerosport 310 panel, how much trimming to the panel sides do you think you’ll need to do to get them to fit on the right side ?


    • Chris French April 21, 2020 at 9:52 am

      I just received my Aerosport carbon fiber panel and it is tight but doesn’t look too bad. I think I’ll need to sand the carbon fiber in the upper left corner of the G5 (maybe 0.25mm deep and 1mm tall). The G5 will overhang the aluminum panel insert in the spot.

  • Marc November 23, 2022 at 4:42 am

    Chris, perhaps a dumb question, but looking at the electrical schema – how does the avionics master switch the avionics on/off if the components (at least some of them) receive power from both the main bus (which is what the VPX switches) and the essential bus (which is not routed through the VPX)?

    • Chris French November 26, 2022 at 1:40 pm

      Marc, most of the Garmin avionics units have two power inputs, one is routed to the VPX and the other to the ESS bus. For devices without two power inputs I added separate diodes between each bus and the device.

  • Hal Yost March 19, 2023 at 11:25 am

    I am beginning to create a wiring diagram for my RV 14. What software program did you use to create your’s. Thanks for your time.

    • Chris French March 20, 2023 at 11:30 am

      I drew mine in Adobe Illustrator, I would not recommend that program as it is a pain to make any changes. If I did it again, I’d research other programs.


Leave a Comment