Replaced a faulty pitot heater relay and got a surprise in the wiring

I swapped out a bad relay on a Cessna 172 last month, and the new one still wouldn't kick the heater on. Turns out the old relay was fine, but the ground wire had corrosion hiding under the terminal insulation. I cleaned it with a small wire brush and dielectric grease, and everything cycled fine. Anyone else seen corrosion that acts exactly like a dead component?

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the_riley23d ago

Pushing that corrosion angle further, I bet half the intermittent electrical gremlins we chase are just bad grounds hiding in plain sight. I had a fuel sender go nuts once, bouncing between empty and full, and everyone said it was the sender unit itself. Nope, the ground lug on the firewall was green and crusty. A little sandpaper and some terminal grease fixed it for about ten bucks. It's wild how a tiny bit of oxidation can mimic a thousand dollar part failure. Now I always check grounds first before I buy anything new.