air started coming out of the defrost vents

2003 FORD F-150
81,000 MILES • V8 • 2WD • AUTOMATIC
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DANNYBOY69
  • MEMBER
  • 1 POST
Just recently, when I had the air conditioner on, as I increased in rpm's the air started coming out of the defrost vents and when the rpms came down it came back out of the front panel as it should. Now it just goes to defrost while it is dialed into panel, dont know if its electrical or the switches, need help.

thanks

dan
May 30, 2008 at 6:59 PM
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MERLIN2021
  • ✓ASE Certified Mechanic
  • 17,250 POSTS
  • ASE Certified Mechanic
Check the vacuum hose that comes in thru the firewall, usually black, it goes to the reserve tank and a check valve then to manifold tap, if it's broken, the system defaults air to the defrost registers...# 15 if you can see it, bottom of the picture.


https://images.2carpros.com/forum/automotive_pictures/62217_AC_Vac_1.jpg


https://images.2carpros.com/forum/automotive_pictures/62217_Res_Tank_1.jpg

May 31, 2008 at 4:19 AM
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