It's been chilly enough in the last week or two that I've been trying to use the heater, but for some reason, even on the "HI" setting, it won't give me hot air.    It just gives me slightly luke-warm air, and at the higher temp settings, it seems to invoke air conditioning which results in me getting even colder. On the passenger side, it will blow hot air, but driver's side is always cold. This is whether or not it is in 'dual' mode with different temperature settings on each