Electrical -no drive lights/trailer/lic plate light

Hey Guys.

So there I was, minding my own business. . . when out of the blue all of my supporting lights went out. I do not have driving lights or license plate lights. I also checked the trailer wiring, and the driving leads are not active there either. Everything else is golden; I have headlights, turn signals, brake lights, reverse lights.

I have checked the bulbs, they are all fine. Fuses, I have checked both the fuse block under the hood and the one by the drivers side. I am thinking that maybe the insulation wore through and grounded out somewhere, but I really don't feel like chasing it from the battery all through the car. Any suggestions what else to check, or where that might have shorted?

199k miles on the blazer, so there is definately some road wear.

Thanks everyone.