That one connector type everyone seems to wire backwards

Honestly, in 12 years of avionics work I've seen so many techs mess up the D-sub pinout on the 37-pin connectors. It's always the same story - they get the female and male ends mixed up in their head. Last month alone I fixed three different installs where someone had pins 12 and 13 swapped on a Garmin GNS 430 harness. Why does this keep happening and does anyone else just label every pin twice before they crimp?

2 comments

2 Comments

emma_smith1mo ago

You said "12 and 13 swapped on a Garmin GNS 430 harness," and I gotta call that out a bit. The GNS 430 actually uses a 47 pin D-sub, not the 37 pin you mentioned. That 37 pin is more common on the old KLN 89B or some audio panels. I've seen plenty of guys mix those up too, thinking they're working with the same connector across different boxes. But you're totally right about the label twice thing, I always sharpie the pin numbers on the wire before I even pull the crimper out.

felix981mo ago

Idk, I actually see it a little different here. Maybe I'm wrong but the original post said 12 and 13 swapped on a GNS 430 harness, and you're right that box uses a 47 pin connector. But I've pulled enough of those apart to know that even on a 47 pin D-sub, people still get the pin numbering backwards on the connector itself. It's not really about the pin count so much as it is about the orientation of the connector. Like, looking at the solder side versus the wire side gets folks every time. I've seen guys wire a 47 pin for a GNS 430 and flip the whole thing around because they counted from the wrong end. So the actual issue the original poster is talking about still holds up even if they got the pin count wrong.