Is there a fuse for my tag light

First, yes, there is a fuse for these circuits. Check that is not blown. If the fuse is good, the wiring to the lights probably has a break, a disconnected lead, or a bad ground causing your lights not to work. Trace the wires one by one to find the problem. You say "no dedicated fuse". Does that mean the lights involved were added on with their own wiring? Or is it that you can't find a fuse indicating that it is for the tag light? Also, check to make sure the bulb is good.