Most likely cause is that one or more of the motors controling the blend air doors have failed. Another possible problem is something fell into the defrost vent and is blocking the door from closing. If air is only coming out of the defrost vent for all vent positions, then you likely have a vacuum line that is broken or the vacuum reservoir (3" ball mounted near right front of engine compartment) is cracked or leaking. Try removing the lines from the reservoir and connecting them directly (to check the reservoir integrity).
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Hi, It is not the blend door, that is for heat/cold changes. The mode door could be the problem, or stuck defrost door.
Your most likely issue is a bad hvac control switch. On older cars, this was operated by vacumm pressure, but on a 2002, it is all electrical. It may be that you need to replace the whole control unit.
when it happened to mine, it was because the arm behind the dash that controls the internal vent doors slipped off
Sounds like you have a vacuum leak - -bad or loose hose or defective diaphragm in one of the vacuum motors
Any of the following can cause this......... 1. Bad a/c - heater controller.. 2. Bad a/c - heater controller inside door operation.. 3. Bad, broken or cracked vacuum line/lines..
The system works off of vacuum. A line from the engine vacuum manifold runs to a 3 inch ball shaped reservoir (mounted to right front wheel well), then another line to the Heating-Ventilation-AC system. If air will only blow out the defrost vent, then there is likely a vacuum system problem. Remove the engine vacuum source line from the ball shaped reservoir and confirm that the there is vacuum while the engine is running. Then remove the HVAC line from the reservoir and connect it directly to the engine line. If this works while the engine is running, then you have a cracked or leaking reservoir.
Check under the hood for a disconnected or damaged vacuum line. The controls are vacuum operated and if the vacuum supply is cut off the system defaults to defroster only.
you have a vaccumm leak defrost is the normal at rest vent setting
Check for a vacuum leak either under the hood or under the dash Check the operation of the vacuum actuated motors Check the operation of the selector switch
install ignition 2002 ford ranger directions
If you are talking about the back seat controls then it is a matter of pushing the power button. The front controls must be set to send air to the upper vents. You will not get flow to the rear seats when any defrost option is selected.