Heater, A/C problems

With the a/c, on lowest fan speed, I get just a tiny amount of cold air, all higher settings, warm air. With the heater, on highest fan speed, i get somewhat hot air, all lower settingshave warm to cool air. Fan speeds all seem normal, just incorrect temp of air. I have checked all fuses and relays in the dash compartment as well as under the hood. Refrigerant level in a/c is full. Could this be a blower resistor problem? The dealership, via telephone, said possibly a door in the ventilation somewhere may be stuck? Any ideas on this? thanks

Don't remember what year you said you had but if your battery was disconnected for a bit of time your heater controls have to be reprogrammed by the dealer. I did a head gasket on a 96 and thought I was doing the right thing by unhooking the battery and come to find out I screwed up and the poor guy had to go to the dealer and pay them an hour labor to reprogram.

Its a 2000. Havent had the battery unhooked, and its fully charged. Any more ideas from anyone?

The blower resistor is there to give you different fan speeds. If the heater- A/C board isn't to blame it might be as the dealer says. I meant to look in my shop manual today but got overwhelmed. As far as I can remember there is a door that adds warm air to the A/C as you set the control to a warmer temp. This may be the one that they are talking about. Another idea could be the hot water control valve that regulates the amount of water to the heater. If it is stuck or malfunctioning you would be trying to heat and cool at the same time. Hopefully I'll get time to go through my manual tomorrow and maybe have some more ideas.