On Thu, 12 Apr 2018 09:48:01 -0700 (PDT), Terry Schwartz
wrote:




One of the important features of those testers is that they provide a load to the
circuit under test, something the LED won't be able to provide.

That too can be addressed with an appropriate resistor across the entire circuit.

Why would I need a load? This is not to test the car battery, it's just
used to check for live wires under the dash or on fuses. I mostly use it
when there is something like the heater blower wont run, or the radio is
dead, or head or tail lights not working. Trailer light wiring... Stuff
like that. My multimeter works for that too, but when I'm under the dash
it's a lot easier to see the tester light up, than to have to look at a
meter. Plus the wire puncture point on them testers is handy.

I should mention that the bulbs in those testers never seem to last very
long. I bet changing to a LED will last me the rest of my life.