Tail Lights Not Working

[cwdavis]

Any help would be great.

The issue is I have no tail lights. Last weekend the passenger side was working. I had blinker, hazard, backup, and tail light. The driver side had nothing. I had about 3 volts getting to the back. After trouble shooting I could not find the cause. But the passenger side still worked fine.
I tried working on it this weekend and found both sides were not working. I now get nothing. Everything in the front works fine.

Thank you