Quite recently my blower *** when placed in cold (to the extreme left) is blowing moderately hot air for sometime before blowing in cold air. I have to turn the AC on and then off for this to stop the hot air from coming into the car. Has anyone seen an issue with the ventilation sys for the 2000 Maxima?

 

Since you are in CA, my best guess would be the vent network in the dash has been baking in the sun. Therefore when you first turn the fan on, the air cools the vent system down thus pushing the hot air out.