Why is my heater not working on 1997 Dodge Ram Van 2500

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?

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1 answer
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.