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vent controls

Discussion in 'Ram Trucks' started by sagedog, Apr 30, 2003.

  1. sagedog

    sagedog Junior Member
    from colo.
    Messages: 2

    When I have the control set on "dash" it works fine below 45 mph. When I get to 55 or so it switches between defrost and dash. this is a new prob. Anyone else have the same prob?:help: :mad:
  2. wyldman

    wyldman Member
    Messages: 3,265

    More info on your particular truck would be helpful here.What engine do you have ?

    It's most likely a vacuum problem.The heater controls are all actuated by vacuum.The default position (in case of vacuum loss) is defrost,so at least the windshield will stay clear.

    In your case,when it switches to defrost at 45 MPH,it is losing vacuum somewhere.This could be due to a vacuum leak,like a burnt or broken hose,a leaking vacuum resevoir (black plastic tank),or maybe you have an engine problem and it isn't creating enough vacuum.Start with checking all the lines and stuff first.

    When the problem occurs,does the truck run OK ? Is it down on power at all ?