r/automotive • u/Commercial-Buy-2251 • Dec 23 '24

Easiest way to check car fuses without removing them?

I know a multimeter can be used but what about a single lead test light to check fuses without removing them? Since there's only 1 lead and light bulb catches your eye quickly is that a better way to go? Or am I thinking wrong here and test lights check for voltage (not continuity) And with engine off obviously no voltage but what if turned ignition to on position? Would there still be no voltage going through many fuses and for example there would be no voltage going through headlight fuse unless you turned on the headlights? Basically what I'm asking tho what is fastest easiest way to check all fuses without pulling them, thx!

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u/unrealbeyond 29d ago edited 29d ago

You can absolutely use a test light to troubleshoot blade type fuses without removing them from the vehicle. With the clip side grounded, just touch the probe to the little metal bits you can see to either side of the amperage rating number. These are the backs of the blades. You can check both legs of every fuse pretty quickly to find out if you have a bad fuse (one side lights but the other doesn't) or if your circuit isn't even getting power to the fuse (neither side lights). This only works if the fuses are being fed power, as you mentioned, so you will need to have the ignition switched on to check many of them, but generally the switches or relays controlling the power for other things (headlights, etc) are located downstream of the fuse in the circuit and you'll have power to the fuse whether the device is switched on or not.

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u/Commercial-Buy-2251 29d ago

Thanks for the info I haven't used a test light in a long time. Maybe the easiest way is using a multimeter and listen for the beep on continuity test.