Please help.........2015 Prius base tail lights not working

I am mainly a Benz guy, but my daughter returned from college with a 2015 Prius base. All of a sudden, the tail lights do not work. And of course, it had to be me who was stopped by a State Trooper for the failure.
1- I checked the fuse first ( under steering wheel) and even though it looked fine, I replaced it. Secondly, I checked the bulbs and they seem to be ok. Swapped the tail light and brake light bulbs out and still not working. Then I noticed that the license plate lights are not working.
Power seems to be available through the harness ( checked each terminal in the main connector for the light unit for power and they all show power. Obviously, the ground is good since it is for all of the lights in the assembly.
Now I am stuck so I have a couple of thoughts.....
1- I assume the fuse is strictly for the tail lights and license plate lights but is there another link somewhere that may be bad?
2- since it would seem highly unlikely for both rear light units to fail without cause where would I start in backtracking the wiring.
It frustrates me greatly because I have learned to do all on the maintenance on both Benzes -including servicing the infamous "no service for life" trans and even replaced solenoids in those as well as a VW Passat, so it is not like I am a total newbie, lol.

Thanks in advance for any suggestions.
Coach Ray

 

Thanks for the info. But basically, none of the bulbs had been changed from what they were initially. They just stopped working. The simple fact that the tail lights and license plate lights all stopped at the same time leads me to believe that it had to be some kind of connector or fuse. But then again, when I check the sockets coming from the harness they all show that they are receiving power. That is why this is so confounding for me. I know any type of electrical problem is difficult to find, but this one has my confused, lol.

 

Tideland Prius- What I meant is that got another light assembly from the parts yard and it had the same results. Brake lights work, turn signal worked but no tail lights. And then , the issues with the license plate lights exists. It would be beyond reason to believe that all of those 3 assemblies would just go bad at the same time.