2002 Ford Expedition

2002 FORD EXPEDITION
84,000 MILES • V8 • 4WD • AUTOMATIC
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DAVID WHATLEY
  • MEMBER
  • 1 POST
Why would the air condition go from the front vents to the defrost vents and then back to the front vents when you give the car gas and then let off the gas. There is no codes in the climat controls read out. The air stays cold the whole time. Thank You Dave
Aug 1, 2010 at 3:50 PM
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JACOBANDNICKOLAS
  • CAR REPAIR CONTRIBUTOR
  • 110,190 POSTS
You have a vacuum leak. The air flow is directed by vent doors in the HVAC system (under the dash). The vent doors are actuated by engine vacuum. When the vacuum is low due to a leak, that is exactly what happens. Check under the dash and the hood for vacuum leaks. Chances are there is a broken or dryrotted hose.

If you are lucky, with the engine running, you may hear a hissing sound from the leak.

Let me know what you find.

Joe
Aug 4, 2010 at 6:01 PM
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