1986 mustang GT here is the deal
I turn on the headlights both outside headlights come on.I Put on the brights and the outside head light on the drivers side goes out andthe inside turns on. Both head lights on the passengers side stay on. It appears that the high beam indicator light inside the car is not comming on or I can't seeit cause it is day light I tried to cover it but couldn't see it so I think it is out. It appears that the tail lights all work. The fog light work but not when the high beams are on I think it is supposed to be that way.
AnyIdeaswhats going onthe light that doesn't come on is brand new.

 

I would replace the light and check for lose wires and make sure you have bad ground

 

check yor connetions and if theyr good youmight need a mutifunction switch

 

The lights seem pretty well connected where is the switch located?