The one wiring test I used to skip and now I never do

I spent 12 years doing avionics installs and upgrades and never bothered with a simple insulation resistance test on bundles that had been sitting in storage. Last month a customer in Phoenix brought in a used harness for a King radio install. Looked fine, no cracks, no chafing. I put it in and got intermittent flags on the bench. Pulled it out, tested each wire to ground, and found two pins reading under 1 megohm. Moisture had gotten into the connector and wicked up the wire. Cost me almost a full day of troubleshooting a brand new install because I skipped 10 minutes of testing. Now I test every used harness before I even quote the labor. Anyone else had a similar issue with stored or pulled parts that looked good on the surface?

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the_jason1mo ago

Happened to me with a bench-tested autopilot servo that sat in a box for two years, worked fine on the bench, then failed on the first flight? Yeah, moisture in the connector pins is a sneaky one, I always hit any stored harness with a megger now too.

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