Testing a computer driver with PP3 and (led) testlight?

Hello guys,

Quick question.
I'm looking into getting either a PP3 or PP4, but the only extra I would use on the PP4 would be the driver test.
Now comes the question: could I do a driver test by supplying power from the PP3 through a (led) test light on a computer signal wire? without frying anything ofcourse.
I assume that when the driver is activated, the testlight will light thus confirming a good driver.

Is this a valid theorie and good practice or not?

Would love to hear your guys thoughts.
Thanks in advance.

Patrick van Herk
6yr Automotive Technician

Now comes the question: could I do a driver test by supplying power from the PP3 through a (led) test light on a computer signal wire? without frying anything ofcourse.

Hey Patrick! You could absolutely use the PP3 with an LED test light like you described to check ground side switched drivers.

Technically, with a typical LED test light, you wouldn't even need the PP3. You could just connect the test light clip to B+ and the tip to the driver circuit.

Is this a valid theorie and good practice or not?

Is it a valid theory? Absolutely. Is it good practice? That's a big debate. LED test lights are 'computer safe' due to their very low current consumption. But that also means they won't load the circuit, meaning they won't expose any voltage drops, if present.

For most circuit testing, I still recommend having a range of alternate loads available. My personal kit has a 921 bulb (~200mA), a 3157 bulb (~750mA + 2A) and an H11 bulb (~4A). Between those, there's enough range that I can pick a bulb that'll load the circuit, but not cook the driver.

There's a few more topics about LED/incandescent if you're interested in reading more:

www.scannerdanner.com/forum/diagnostic-t...se-a-test-light.html

www.scannerdanner.com/forum/diagnostic-t...control-current.html

Hey Tyler, thanks for the reply. I might have to make some test bulbs soon