noise from passenger side, burning smell, heat turns cold

Strong burning smell resembling oil/electrical/etc.smell.in cabin when engine is running with AC/Heater turned on. Heater, when turned on, sometimes will run heat for a few minutes and all of a sudden, without provocation, change to blowing cold air. Also, annoying rattling noise, almost regularly, emanate from behind glove box/dashboard at front passenger's side.