License plate lights question

[billnorman]

that's D.C. A better checker than a voltmeter is a test light. I use a brake light bulb with meter leads soldered to the contacts. Wrap the bulb socket in tape after you attach the wires to it. If the bulb lights brightly, you have a good connection and a good ground. You need power, volts doesn't always mean you can get enough amps to run anything.