I have a 91 Aerostar van. My heater was not blowing out hot air, just luke warm to cold air. I replaced the thermostate with a new one from autozone. not I get even cooler air. can some one tell me what to do. I have checked all the vacuum hoses. it has antifreeze in it. Im lot on how to get HOT air. I have found two small hoses going from the thermostate to the heater core, one of them is hot to a point then cold, the other one coming from the core is just cold.