2001 Honda CR-V reverse lamp problem

I have one reverse lamp that works and the other will not. I changed the bulb. Still not working. I checked the voltage and it's at 8.50 volts at the socket. Any suggestions? Glenn

Sounds like a bad ground. You should have full battery voltage at that socket. Beyond that I would suspect a bad socket or a melted connector.
Has water gotten into the light assembly or has that corner of the car been in an accident?