Help please
 

Ok so my wife 3.5 2005 Altima had a few issues this last year and now she is complaining of a burning or "fire" smell as she puts it.
When the a/c or heat is on...coming through the vents.
Some history.
At the end of last year we had the belts change [alt. a/c etc.] and Firestone installed the wrong belt and burned up my power steering pump.
So we took it to the dealer on Firestones dime to have a new pump and the correct belt installed.
Then in January the Alternator failed.
We replaced.
With a new aftermarket one which failed after 4-5 months.
Had it checked and rebuilt.
Then in March I re-charged the A/C [have to add a little every year or so ].
Then the passenger side H.I.D [factory] burnt out. Replaced..
Then in May the Drivers side went out [have a new bulb but haven't replaced it yet.]
At about the same time we had an oil change done and all filters including the cabin filter.
After about a week or two she started to complain of the "hot" smell.
Oil is good tranny fluid good and coolant good.
So the other night she started the car and went to grab something from inside and I heard this slight rattle coming from the engine compartment but not from the engine itself.
Possibly alternator or cooling fan...not real sure.
So to wrap up the car does not run hot the alternator is putting out correct voltage . Also has a new battery.
So what could be causing this "smell"?
What should I check next???