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Fabricating avionics wiring harnesses

prkaye

Well Known Member
I'm going to be upgrading some avionics (nav/com, audio panel). I'm wondering about attempting to fabricate the wiring harnesses myself... I believe the radios come with connector kits for this. I've never fabricated a wiring harness before. Is this very difficult? Could anyone point me to a good tutorial or guide?
 
Like rivetinng

Like riveting it is easy to pick up. One just needs to be a little more meticulous about keeping everything neat and using the proper tools; no mickey mouse stuff. Garmin G3x install manual (free online) and Steinair are great places to start.

It really is easy, just a lot of step and repeat.
 
The most important part is having the correct tools and learning how to use them properly. Crimpers, wire strippers, wire labeling printer. I wired my entire 14A and it was easy once I developed the skills.
 
Proper crimpers are not cheap but you can find them on auction sights or used on here. They will outlast you so get good ones. Don’t even think about automotive stuff. It’s not hard to do but does take some time. I made a few mistakes on my VFR RV -8 and they took a long time to sort out. If labor was a factor, much cheaper to buy than make if you are inexperienced. Get the AeroElectric Connection book to start with. The wiring was one of the more fun parts of the build and so nice to see everything light up w/o smoke when first turned on.
 
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I found that Steinair's videos were really helpful. And I bought an inexpensive continuity tester that beeps when it has zero resistance, and used that to verify my cables.

I started with some of Dynon's pre-fab cables, some connector kits and some extra wires. It took some time but wasn't difficult, and the install manuals made good guides.

Dave
 
Phil,

While you are upgrading, I recommend you do all this wiring with the panel on the bench. From that you can add connectors to mate it to the rest of the plane. This will pay dividends when time comes for maintenance or modification.

Carl
 
Another point to consider is having service loops, basically enough slack in the wiring that you can make changes later on... such as changing switches or, I wish my plane had this, being able to access the connectors on the center stack without having to remove all the radios and trays...

Somebody correct me if this will lead to RF interference, but I would keep separate the CANbus, the serial and discrete lines, the power and the ground lines, just so it's easy to find things later on.

There are minor upgrades to my panel center stack that I won't even consider because of the hassle of relatively minor rewiring.

And you might consider running stubs, labeled, for things like discrete inputs that you might use in the future.

Lastly, for the Garmin, IIRC there are some preferred serial ports for connecting various components, and those are well-hidden in the installation manual. To improve the odds, copy the serial port usage in the installation manual. And the course on installation sounds well worth while!
 
I second this motion

The guy who built my -9A did a great job, but having done far too much spelunking under the panel, I can say that it was NOT designed for future maintenance/upgrades!

+1 on the Stein Air videos. What a great resource, as is their online store. If they can teach me how to create D-sub connectors, they can apparently teach anyone to do anything.


Another point to consider is having service loops, basically enough slack in the wiring that you can make changes later on... such as changing switches or, I wish my plane had this, being able to access the connectors on the center stack without having to remove all the radios and trays...

Somebody correct me if this will lead to RF interference, but I would keep separate the CANbus, the serial and discrete lines, the power and the ground lines, just so it's easy to find things later on.

There are minor upgrades to my panel center stack that I won't even consider because of the hassle of relatively minor rewiring.

And you might consider running stubs, labeled, for things like discrete inputs that you might use in the future.

Lastly, for the Garmin, IIRC there are some preferred serial ports for connecting various components, and those are well-hidden in the installation manual. To improve the odds, copy the serial port usage in the installation manual. And the course on installation sounds well worth while!
 
Make sure you have developed a complete set of wiring diagrams for at least the connectors you are going to install or revise before you start the actual wiring. Better still is to have a complete set for the entire aircraft. Then revise these to as-built once you have completed and tested the systems. Without a road map (wiring diagrams), you won't know where you are going, and will likely end up taking a much longer route (more fabrication time) and could end up with a real rats nest that is difficult to trouble shoot.

Just a strong suggestion from my career as an Electronics Engineer.

Cheers,
 
Lastly

All the advice above is good, but the most important advice:

DON'T USE ONLY ONE COLOR OF WIRE.

Trying to troubleshoot a wire harness with all white wire is crazy.
 
+1 Stein Air, I could get some stuff cheaper thru ACS, but the crew at Stein has been incredibly patient with me as I made some changes to my wiring harness, and I love to support small businesses that give great customer service.
 
... I believe the radios come with connector kits for this.

The connector kit containing the DIN plug, connector pins, etc is a separate purchase / line item on Garmin products. Same thing applies to pitot and static air fittings.
Steinair.com is your one-stop shopping source.
 
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