Ford Repair Questions? Ask a Mechanic for Answers ASAP
hello yes . If you lose the vacuum supply for the HVAC control in the dash of your vehicle it automatically defaults to Defrost . there is a vacuum hose from the engine that runs through the firewall to run and supply the HVAC control head . A loss of vacuum due to a cut or chewed supply hose will cause your issue . . You will need to locate the leak and repair the cut or chewed vacuum hose .