I have a 2015 Nissan rogue SV and I was sitting in my car blasting the heat outside of work one morning. I turned off my car to go in and when I went outside to go home later that night, the vents were blowing winter air, despite both thermostats being set to 90 degrees. I realized that the two passenger dash vents blow heat, so I just shut off every other vent and warm up my car twice as long in the mornings, but does anyone know what this is and how I can fix it?
this sounds like a blend door issue to me. inside your dashboard there are a bunch of ductways for the air and electrically controlled doors that direct the flow of air. these can get stuck or break, causing heat and/or a/c to come out certain vents. it could also be a clogged heater core. both require some intense dashboard disassembly unfortunately