alright, 1988 gxl car, s5 tails

everything has been working fine for 6 months....

now the passenger side reverse light wont work, and the taillight right beside it doesnt work....but the next taillight beside the blinker works, and the blinker light works.

i replaced the bulbs.....still doesnt work.....

help please?

 

if it is just the passengers side, I would be looking at the plug and connections (as well as the sockets).