Driver-side low beam was out so I went to the auto parts store to pick up a new one. Well it still won't light up:( Using the ohm setting on a multimeter, you can check standard household light bulbs to see whether or not they are defective. Good light bulb = high resistance, since the filament needs to be of high resistance for it to glow. I know this doesn't work for all types of lights (like CFL), but will it work for my light bulbs in my vehicle? They are standard or "OEM" (not HID's). I'm almost certain I didn't purchase a defective bulb. So now what? Can I check the actual harness in my vehicle? These light bulbs operate on DC, correct? Would I test Volts or Current? Will it matter? I will check the opposing harness for reference, i.e. I'm getting 10mA on my passenger side low beam harness so I should theoretically be getting 10mA on my driver side low beam harness.