2000 Pontiac montana starts with a jump no headlights

So I have a 2000 Pontiac Montana that will start if I jump it
but the headlights don't work and everything else it does
still it seems to be. Originally it was seeming like it was the
alternator but I tested it and it was good and the battery
said it was good and I checked all the connections and
they look good but I started it today and it runs but the fog
lights work the headlights do not and the headlights are
still good. I'm kind of at a loss I don't know much
mechanically with it so any help would be appreciated
thank you