For some reason my heater is only blowing cold air. I check the hoses running to the heater core through the fire wall, they both are hot. The coolant level is full. I took a part of the dash off to access the controller unit, the tempature **** seems to be controlled by a wire connected to the control **** and seems to be working, you can hear the door moving. Any suggestion other than what I have checked?

 

The thermostat could be stuck in the open position. Does it take a long time for the car to get into operating termperature?

 

No, not at all. I start it and let it run for about 5 mins and its at operating temp.

 

My only other suggestion would be to check all the solders on the pins for the controller unit. A hairline crack in a solder could make the unit not work, but not be very visible. But when that happened to me, the air would only blow out of the top defrost. Since you didn't mention that symptom, probably isn't the answer.

MRR