What could be wrong with my AC/ Defroster unit?

Seeing as how they're separate circuits, let's look at 1 thing at a time....1st, the window....its only the passenger window and it doesn't work from either switch? Leads me to suspect either a wire that got pinched or a bad motor. Ac/defroster does the blower motor kick in? Blown fuse? Are you able to decide where the air blows out from? And the radio, is it getting power? Aftermarket radio? Cigarette port working?

1) It is sometimes also the drivers window (though rare) but the passenger window doesn't work from either switch. I have changed the window regulator twice already. 2) The blower motor for the AC/defroster unit does not kick in. They don't turn on at all. However they sometimes turn do turn on but I don't understand why or how that happens. 3) The radio is getting power, but the volume will randomly turn all the way up or down and it will change stations. Cigarette port also works. 3)

As far as the ac/defroster goes, run wires from battery to cut the rest of the circuit out and test just the blower motor for the heat/ac....passenger window make sure power is getting to the switches....radio sounds like time for an upgrade