Hot take: Using a multimeter vs a test light for troubleshooting a 12v system in a Cessna

Spent two hours chasing a dead transponder in a 172 last week with my Fluke, pulling schematics and checking continuity everywhere. Swapped to a simple test light and found a bad ground at the tray in like 5 minutes because the light showed voltage drop that the meter missed. Anyone else find that the old school test light catches those intermittent connection issues faster than a digital meter?

2 comments

2 Comments

theawest21d ago

Oh man, that's a classic. In my experience, a test light loads the circuit way more than a meter does, so it'll show you those high-resistance connections that look fine on a Fluke. Did you happen to check the ground stud itself for corrosion before you started probing, or did that bad connection only show up under load?

the_anthony21d ago

Wait I used to be a "meter or nothing" guy but you're making me rethink that test light trick?