heater control issues

Sounds like a couple issues - first check for vacuum hoses under the dash that may be disconnected. Or a vacuum motor could be faulty for ventilation position. Not running on high could be a faulty blower motor resistor or a bad blower motor itself.

check you control head for a vacuum leak. you also should make sure you have vacuum going to the control head if all that checks good give me a call at 375-0098 and i can give you some more pointers hope it works Brandon

A lot of dodges have a problem with the knob itself breaking that changes from one place to another. Take the knob off by pulling off then use needle nose pliers to turn the control and see if it works.