Can you swap left and right side bulbs and see what happens?

 

That is called voltage drop, and it's the reason that all voltage tests have to be done with the component in the circuit, and the circuit on. It only takes one tiny strand to show that 12v with the bulb out, because current doesn't flow in an open circuit. You have to have the circuit as it is working to know if there's enough voltage for it to work. Put the bulb in and use a t pin or something to back probe the wire. If you don't have nearly 12v there, move closer to the battery until you do. Somewhere between those points you have excessive resistance - corrosion or wire damage.

 

Thank you all for the replies. I'd a long distance road trip planned the next day so I got impatient and bought a used tail light assembly from a nearby wrecked parts store for $60. When I pulled out the plug I didn't notice any green corrosion so my guess is something's wrong with the circuit board on the tail light assembly even though everything looked normal to the eye. I wish I spent a little more time outside but the freezing cold that day and my trip the next day forced me to make a quick decision.

 

this could have been caused by a leaking tail light ,nissan put out a notice a couple of years ago how leaking tail light will affect the computer and screw up your cvt trans so who knows what elese it can screw up . it was shown to me my anissan mech how the water leaks in even through it is 2 sealed