Thanks for the advice. I'm beginning to agree that it's a plugged heater core because last week I had the vehicle running and physically verified that both passenger and drivers blend doors were at the full heating position by removing the actuators. The air temp was warm but not hot and this was with either the floor vents or upper vents.

Is there any other damper involved with the air distribution besides recirc and mode? I sometimes hear this weird hiss from the passengers dash during heating mode. It's difficult to describe, it's sort of like a vacuum leak noise but there is no access to visually check anything past the glove box.

Mike

 

That is usually the a/c system, they hiss like that when they are low on charge.

 

Thanks, can you explain why the A/C comes on when the controls are in low auto, no defrost or recirc, temperature setpoint at 78 deg F (both sides) and outside air is about 40 deg F. Also, the snow flake symbol is not on. I was told by a Dodge service advisor that this is common on vehicles with automatic climate controls. I find this odd and also a waste of gas.

Mike

 

when it's in auto it can do whatever it thinks it needs to achieve it's goal. It usually likes to know the air is dehumidified.

 

FINALLY fixed the problem. It was the heater core, new core cost $60 canadian and it took less than an hour to replace. Thanks again.

Mike