The AC blows cold air on every setting but 90. Below 90 you get the same cold temp regardless of setting. At 90 it blows hot air . . . thoughts?

 

What's your vehicle and model? I haven't encountered this issue, it's usually the a/c not working or blowing hot air when turned on. They say the common cause for hot air blowing is loss of refrigerant. But in your case, it could either be an obstruction inside the refrigerant circuit that prevents refrigerant from circulating inside the A/C system, or a blend air door stuck in the HEAT position of the HVAC unit preventing air from flowing through the A/C evaporator. But like most people here, i'm just guessing. Have a professional technician take a look at it for proper diagnosis. Hope it gets fixed.

 

Maybe I'm a dork but shouldn't the 90 setting be calling for heat? So are you saying at lower settings - say 65-75 - it's blowing cold vs a more blended setting?

 

Yeah - this makes no sense.