Help with crazy A/C functioning

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Aug 5, 2012 | 02:39 PM

wgm114

Thread Starter

Mountain Pass

Joined: Aug 2000

Posts: 144

Likes: 0

From: Centreville, Virginia

Help with crazy A/C functioning

My 2001 F250SD 5.4L is doing something odd. When I have the A/C on and accelerate, it shifts from blowing out cold air from dash vents and goes to blowing lukewarm air out from the defrost vents on top. As soon as I decelerate or tap the brake pedal, it switches back to the dash vents and blows cold again. Even minor acceleration switches the air from blowing out the dash vents to blowing out the defroster vents.

Any suggestions or is this a known issue?

Thanks in advance.

Aug 12, 2012 | 09:24 PM

Nsaan

Posting Guru

Joined: Aug 2010

Posts: 1,002

Likes: 1

Quote:

Originally Posted by wgm114

My guess is you have a vacuum leak somewhere, I think the ac system uses engine vacuum to operate the vents, when you accelerate it opens the throttle butterfly and you loose the vacuum, it has enough to operate it at slower speeds but that is it.