Passenger’s side dip light is dim. High-beam works fine. Checked and cleaned relays and fuses. Grounds seem okay. ~ Can a mono bulb go bad in just one of its functions and possibly work if replaced, or, is this strictly an electrical problem? Thanks !
Pretty sure the bulb has two filaments so one could go bad. You could always swap in the one from the other side to confirm.
BobPhx1…Thanks for your feedback. Here’s what happened: Swapped bulbs and expected to see no change. The filaments in both bulbs looked intact and was resigning myself to this being a hide-and-seek grounding problem. HOWEVER- I must have acidentally re-set whatever was shorting during the tug-of-war with the bulb fixtures through the wheel wells. After the bulbs were swapped, hi-beams and dip lights worked perfectly. 
~THANKS AGAIN
Excellent! Possibly a dirty or oxidized contact in a bulb socket. Here’s to small victories!
Bob Brackney