1995 caravan - heat coming out cold

The air coming out of the vents is cold when I have the heat on. What should I check. I do have a new thermostat.

Make sure the blend door is opening. Feel the heater hoses going to the heater core to see if they are both about the same temperature. If one is significantly hotter than the other, the heater core is clogged or restricted. How old is the waterpump? Waterpumps wear out, reducing the flow of coolant through the heater core.

If you can get to them watch the actuator and door. Here's what they look like: http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/10/c9/71/0900823d8010c971.jsp Figures 4 & 5.