Dropped $280 on a used harness that turned out to be a paperweight

I bought a used avionics test harness off a guy online back in January, and it looked fine in the pics. Got it in the mail, plugged it in, and nothing. Turns out the pins were corroded inside the connector and one of the wires had a broken shield buried under the heat shrink. I spent about four hours chasing a fault on a Garmin GNS 430 before I figured out the harness itself was the problem, not the unit. Took it to a buddy who does bench work and he said the whole thing was scrap, the connector shell was mismatched anyway. So I ate the $280 and a day of labor I could've spent on actual billable work. If you're buying used harnesses, test continuity on every pin before you hand over cash, or just pony up for new. What's your go-to way to check a used harness before you install it?

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henry_hernandez27d ago

That line about the broken shield buried under the heat shrink hits home, had the same thing happen to me on a used tray I picked up for cheap. What I do now is a basic two part check before any cash changes hands. First I ring out every single pin end to end with a meter and wiggle the connector while I do it, because a pin can read fine until you move the shell a bit. Then I do a pull test on each wire at the backshell and look for any spot where the insulation looks heat shrunk over a splice. If the seller won't let me test it in person I just walk, honestly not worth the gamble at that price.

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