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ac outlet issues


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rep
New User

May 4, 2009, 3:38 PM

Post #1 of 3 (1363 views)
ac outlet issues Sign In

I have a 97 F150 small V8. The ac will only blow out of the defrost vents and the floor vents. What's up?


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

May 4, 2009, 4:27 PM

Post #2 of 3 (1360 views)
Re: ac outlet issues Sign In

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 resevoir (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.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



rep
New User

May 5, 2009, 5:47 AM

Post #3 of 3 (1356 views)
Re: ac outlet issues Sign In

Thanks for the info Hammer Time.






 
 
 






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