Oddly enough, this actually only happens when you have a window rolled down. Correct? Having a window rolled down creates sucking effect, if you will from openings in your vehicle.
I recently discovered this also after having an accident. More then likely a piece of molding has either been shifted out of place or corroded over time. Either way, this is why you have the problem and the molding will have to be replaced in order to block this hot air there.
Correction:
If you have a manual, Grab hold of the shift nob and twist hard to the left. It will unscrew and come off. Then remove the 4 screws holding down the plastic shifter boot base and slide the whole thing up and off. I'm not sure how this is accomplished with an auto, but the goal is the same, to get at what is underneath the shifter assembly.
After that you'll find a black square shaped rubbery material that is acts as a secondary shift boot that is designed to keep the hot air from under the vehicle from comming inside. It is torn. It is also held on by four screws/bolts, some are hidden under the carpet. You can either replace the boot or try to fix the old one.
The reason it gets so hot down there is that the exhaust pip runs right underneath the shifter on the drivers side, an Nissan opted not to put in a very functional heat sheild.
Check your coolant levels, and check your thermostat - it may need replacing. Also check your heater hoses to ensure they're not leaking.
Blows on #4 only? I would replace the resistor. #4 speed by-passes the resistor.
You have a defective HVAC resistor pack. Replace it. Mine went about 6 mths ago and it was covered under the warranty. Check that out before you pay. Answer Mine went...replaced resister. works fine...took about 5 minutes!
you probly need to change your belt. Addition: I have the same problem in my 2002 Xterra. It is the compressor clutch engaging/disengaging during normal opperation of the A/C system. Tightening belts will do nothing for the intermittent squealing belts on a 2002. On most vehicles, you could just change the clutch assembly .... However, not on the 2002 Xterrra. I will need to replace my whole compressor, which sucks b/c my A/C blows perfect cold air. My 2 cents.
AnswerReplace the blower resistor.
I have a 2006 Altima and it is doing the same thing.
that is bad... go get it checked up on!
You use the TNT and put it in his coffee cup and it blows up then you get It
MY 05 NISSAN MAXIMA BLOWS HOT AIR. WHEN THE CAR HAD 15000 MILES WE TOOK IT TO THE DEALER FOR THE SAME PROBLEM AND THEY SID THE COOLANT WAS A LITTLE LOW AND THEY ADDE SOME. BUT THE PROBLEM HAS PERSISTED AND NOW WE HAVE TO TAKE IT BACK AGAIN. THE CAR NOW HAS 22000 MILES.
2005 nissan altrema 4 cylinda heat on blows cold when i speed up warm air will come out
TRY THE AIRCONDITIONING BELT
Check to see if the switch is any good . Most of the time it is the switch.