Cars

You may have a ground wire not making connection. Check all the wires for clean and snug connections. If you can, turn on the lights and put a voltmeter on the positive wore and use the meter's ground to see if you have any power. If not, you may have a break in the wire coming to the light. Normally both lights are run off one wire, so if the first one works, that makes your check shorter for an open wire. Clean your connections with a lite emery board, just enough to scuff the connections in case they are coated with residue. Your wife's old nail emery board will work. Clean all the connections.