my rear taillight is not working?
the bulbs are good and the brake light,back-up lights are all fine. I tested the power to the socket and out of the 3 connections i got, 5 volts on one,12 on the other and one is ground . what could be the problem?

 

I'd try replacing the bulb. 8 years old, might be time.

 

the bulb has been replaced

 

I'd suggest that the 5 volt reading is your problem. Which wire did you get it on? If it's the tail light (as opposed to brake / directional) wire, that's where you need to begin your search. I'd suggest tracing that wire back and seeing where it drops from 12 volts down to 5. Good luck!