97 Montana No defrost \ Low air flow


New member
New member...1st post. I have read about a dozen posts with these same symptoms of losing air flow when selecting heat but have not found anyone that resolved the problem.

I have 97 Montana Transport. With the temperature selector in cold position I get good air flow however I lose almost all air flow when I select full heat. If the heat selector is placed in the mid position I get some warm air but it is reduced flow. I also do not get defrost air hot or cold. I can find 1 electric (Blend door I think) and 2 vacuum actuators (One seems to select floor/dash vents and one selects heat/defrost) and they appear to be moving correctly. The inside/outside selector door (Behind cabin filters) opens and closes. Filters in or out no difference. Heater core gets hot and air blows through the core when I select heat. I have as many of the covers off as I can find, glove compartment removed.

Any ideas appreciated.