Number Plate Light Not Working

[seanyfp]

Hi there, ive noticed my number plate bulbs were not working, so i changed the bulb to a working bulb and no good. had a quick look at the harness for the wires that fit into the bulb harness, nothing obvious. tried to find a fuse location online and nothing. 

what could it be?

cheers

[Multispacer]

If they're both not working, I would think a good place to start is the earth return wire? You can do a quick check with a cheap multimeter. With power off check the earth return side, by clipping one of the meter terminals with a crocodile clip onto a piece of the metal bodywork and try each of the terminals with the other meter probe, you would expect one of the lamp base contacts to show a very low amount of Ohms to earth.

If they are both OK, then you can switch the multimeter to DC volts and check the supply voltage coming into the lamp contact base [after switching on sidelights]