I borrowed my dad's truck so I could tow a car. Went to install a wiring harness for the trailer lights. I was going to use the license plate wires for the parking lamp hook-up. I could not get the multimeter to read... so I unhooked the license plate wires at the connector and jammed the multimeter up in there. Well, after that, the parking lamps won't come on. I have checked all fuses. All were good. The license plate lights and front and back parking lamps will not come on. Any ideas??

Thanks in advance,
Kbelky