2002 Ford Windstar dash air flow

2002 FORD WINDSTAR
48,000 MILES • 6 CYL • FWD • AUTOMATIC
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RGOSCHEY
  • MEMBER
  • 1 POST
It started that when you switched to dash and started to drive or when you went up a hill it would automatically switch to floor heat then to windshield the eventually back to dash. Now it stays on defrost all the time no matter what the contol switch is set. How do I fix this?
Thanks Rick
Sep 7, 2010 at 8:34 PM
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WRENCHTECH
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 20,761 POSTS
The mode selection is done through a series of air doors that are operated by vacuum. When there is either a partial or total loss of vacuum, the system will default to either defrost or on some vehicles, heat. Acceleration can also have an effect on the doors for the same reason.

Look under the hood for a small black plastic hose coming through the firewall. Follow it to the vacuum source looking for any breaks, cracks or leaks. Also follow any other lines that branch off because they may go to a vacuum reservoir (storage tank) and a leak there will cause the same problem. Using a vacuum gauge to determine if you have full vacuum at any given point is the best way to find it. You can cut into the line anywhere and splice it back together with a piece of vacuum hose. Find the broken line, you found your problem.
Sep 7, 2010 at 8:35 PM
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