Heatstrips could be on with ac
low on refrigerant or the compressor isn't running..
if the compressor is Running you are low on freon, if its not then you have a electrical problem
Make certain the compressor is running. If it's not running, have the refrigerant level tested.
that is too low of pressure.
Recharging the system with Freeon Gas or Possible replacement of the Compressor! Just maybe, the belt needs tightening.
Usually compressor not running or low on refrigerant. And yes it is supposed to be warm
If the compressor is running, the blower is blowing, and there's no cold air, you need freon. If the whining is from under the hood, the compressor may be damaged. That's what happens when running without freon.
because the compressor isn't getting enough tourque
A bad alternator will cause a battery to go bad. It does not have an effect on the air conditioner.
Compressor not operating.
The rear air conditioner of a Sienna will begin to blow warm air if the vent is incorrectly set. This will cause warm air to enter the vents rather than air conditioned air.
My 2002 blows warm air when the rpm goes down significantly (when I don't clutch)