Old bulb is good...Replaced with new bulb just in case and it still doesn’t work. Only one low beam, is out. Fuse is good. Both High beams work fine. Ideas?

 

Check the wiring going to the bulb and the socket.

 

Take a close look at the terminals in the bulb socket. They get scorched sometimes and lose connection with the bulb pin.

 

Yup. They can arc at the connection which melts the bulb wire into the plastic and corrodes the socket plug causing it to not make a connection. After fixing this several times on one of my vehicles, I finally replaced the sockets and haven't had a problem since.