Thank you both. To be specific:
the blinkers and hazard lights work and blink both sets of brake lights. When I turn the lights on, or step on the brakes, no taillights.

It is a 20A fuse, the one at the bottom of the fusebox, but it's not tail/blinkers. Just tail lights.

I'll try removing all bulbs and see what happens. I'll also inspect the wires for fraying, etc.

Thanks!

Tom