the heat blows out the defrost when it should blow out floor vents only
Some ford truck hvac systems will default to the defrost setting if the is a problem with the electrical or vaccum parts of the system. I encountered a ford truck that had a mouse living under the hood and chewed through the vacuum hoses and would only blow on defrost.Do a good visual check including electrical,such as fuses etc...
The fan has two different ways to turn on in the Escort. Check the temperature gauge and its circuit as these control the fan when the engine heats up.
you have to trick the ac computer by shuting it off then restarting it...
vacuum leak. look at the vac pump under the hood on the pass side and check the hoses for dry rot or cracks
you have a vacuum leak. defrost is the default when a vacuum leak is present.
The AC does not blow on the main front vents. Only rear and defrost.
why dont bottom vent doors not open on 2001 gmcsonoma
depending on the year there should only be one
The default for heaters is to go to defrost if there is a problem in the system. You will have to get under the dash to find the problem. Probably best to take it in as they can get tricky without diagrams depending on the system
You have vacuum line leaks somewhere.
check your vacum line to door by the gas pedal for vacum