There are actually a few symptoms that are occuring. 1 - the heater doesnt warm up at high speeds and barely at low speeds. 2 - When accelerating up a hill the defrost blows out air instead of the current setting (I assume a vacuum problem) but cant find a vacuum check valve that applies to this van. 3 - the blower motor only operates on high ( I assume a resistor malfunction). 4 - while idling there is a funny noise and (I am assuming it is the idle tensioner)Could alot of these issues be because of the idle tensioner?
Why is my heater not working on 1997 Dodge Ram Van 2500
If your Heater system keeps going into defrost with out you selecting that mode, that generally means that the auto climate control is going in to a limp home mode because there is a problem with the system, Best to get your Climate Control System scanned to see what is wrong.