Stop trusting those cheap pin testers on 28V DC feeds

I watched a guy last week at the Orlando hangar chase a ghost fault for 3 hours because his $15 pin tester showed 28V on a feed that was actually dead. The load was only 0.4A so the tester lit up fine, but the wire had a break under the bundle. How do you guys verify voltage on low-current loops without pulling the whole harness?

2 comments

2 Comments

luna_wright1mo ago

Man, I feel this one deep. My own cheap tester once told me a brake light circuit was live and I spent an hour cussing out a perfectly good tail light assembly before realizing the tester was reading phantom voltage from a neighboring bundle. These things are great for finding a hot wire, but they lie like a rug when the current is weak. Now I keep a proper low-impedance meter in the truck and use the old trick of putting a load on it, like a 1157 bulb, before trusting anything on a 28V loop. Still, I won't lie, half the time I just poke the wire with my tongue and hope for the best. Kidding, but only half kidding.

ryan_shah381mo ago

Trust the meter over the tongue every time, @luna_wright. That phantom voltage crap got me too until I started loading the circuit first. Cheap testers are only good for finding wires, not for judging if they actually carry anything.