Problem resolved! In the course of troubleshooting, i cleaned all sockets with sandpaper and alcohol, bent tabs up/out, checked fuses, and tested each wire/plug with a multimeter. Finally, I bought all new bulbs for both rear light assemblies. I think i may have had incorrect bulbs to start with The correct bulbs: (see pic)* Top bulb is for blinker. 21w with a single filament and single contact on the base.* Bottom bulb is for brake and tail marker. 5w / 21w with two filaments and two contacts on the base

 

Glad you got it sorted. Sometimes it's the simplest thing.