2006 ford f150

Ok Guys here is my issue when I turn my light on dash light go out heat don't
work and shifter locks in park. It also does the same thing if I don't turn the
lights on and turn my heat on nothing works either was. but my headlights do
come on when I turn the switch. And if I do try the heat without the light being
on the dash lights come on but very hard to see and with heat being on and
light switch off you can see headlight and other light on outside. I just put in a
new alternator and a starter. It's driving me crazy trying to figure this out any
idea's thanks.