Spent like 4 hours chasing a ghost voltage on a Garmin G3X install

Turned out I just had a bad ground connection on the backshell, cost me a full Saturday and $60 in test leads I didn't need because I didn't check the simplest thing first anyone else dealt with a phantom reading like that?

3 comments

3 Comments

patricia326d ago

The 37 pin D-sub on those G3X backshells is a real pain. I actually had a similar issue but it turned out to be a tiny nick in the wire insulation right where it entered the backshell, not the pin itself. The wire was barely touching the shell and causing a phantom voltage that jumped around like crazy once the avionics warmed up. A lot of people overlook that the backshell can physically pinch the wire bundle too tight and wear through insulation over time, especially if you use a cheap boot or don't leave enough slack. I always use a good quality metal backshell with a proper strain relief clamp now and leave an extra inch of wire inside so nothing gets crushed. It's stupid but chasing those little voltage ghosts taught me more about Garmin installs than any manual ever did lol.

quinnm777d ago

cost me a full Saturday" - did you ever find the actual bad pin in that backshell?

the_jake6d ago

Actually found it tucked behind the 37 pin connector on the backshell. Turned out to be pin 22 on the plug, not the receptacle. I used to think those backshell issues were always just bad crimps or seating problems, but that Saturday changed my mind completely. Now I always check the pins themselves before chasing anything else in the harness.