When I turn it on a higher speed the Sri light turns off and only warm air comes out

defroster,cabin heat not working at idle after vehicle is warmed.Systems work when vehicle is driven,cold air resumes at idle,red lights,stopping,etc.Thermostat?

Defroster,cabin air runs cold at idle,however ;upon driving all systems heat up.I have tried warming up vehicle 15-20 minutes,defroster,heater still won't work till I drive.Stopping at lights,I notice temp decease in cabin

I just bought a 2011 nissan xterra X but I am 5' tall and my xterra driver seat does not raise. I am actually sitting on a pillow to drive....uncomfortable. Is it possible to replace the seat to an 8 way manual drivers seat? And if so, where can I purchase the seat? bettyboopeht@yahoo.com