After reading a couple of threads about this, I decided to help my neighbor with a short term fix, by running a jumper wire from the outboard headlight socket (the tan wire) back to just one taillight sockets(the purple wire). All four taillight bulbs are now working for night driving with the headlight swtitch in the "normally on" position. The brake and turn signals work properly😁😁😁 (Taillight filament in the bulb is the thinner/upper one (and dimmer)...the thicker/lower one (and brighter), is the Brake/Turn signals/4way Flasher functions
The true fix sounds like a real Science Project. I'm led to believe there is a headlight control module completely hidden someowhere under the driver's side of the dash that could be the culprit !!! If THAT'S TRUE😨😨 Where EXACTLY IS THAT MODULE LOCATED , and what kind of connector, wire colors, number of wires, manufacture part no. ,shape, ,etc.can help us identify it!!😕😕
...AND, A PICTURE showing where it's installed would be perfect!!!