That reverse polarity day that almost cost me a $12,000 repair

I disagree with the guys who say you should always trust the wiring diagram over your own eyes. Last Tuesday I found a mislabeled pin on a King radio harness that the manual said was ground but was actually hot. Has anyone else caught a factory error that could have fried a whole panel?

2 comments

2 Comments

jana_henderson5213d ago

You're right to question the manual. I found a King radio harness with a pin labeled "DATA OUT" that was actually carrying power straight from the bus. The factory had swapped the pin assignments on a batch of radios in 2018. Always use a multimeter to verify every pin before you plug anything in. That $30 tool saved me from frying three brand new Garmin units on a Baron panel last spring.

anna_hill13d ago

Yeah "always use a multimeter to verify every pin" is the real lesson here. I had a similar thing with an old Bendix King radio where the pinout diagram in the install manual was totally wrong for the power pins. The diagram showed pin 7 as ground but it was actually +12V constant. If I had just trusted the book I would have shorted something bad. The factory does make mistakes sometimes and you gotta check everything yourself before you let the smoke out.