2001 Ford F150 Blower

2001 FORD F-150
135,000 MILES • V8 • 2WD • AUTOMATIC
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DALE OWEN
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  • 1 POST
When I accelerate my blower while the AC is running switches from the vents to the defroster. When I let off the gas peddle it switches back to the vents. What is causing this and is it expensive to repair?
Aug 15, 2008 at 1:22 PM
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2CARPRO JACK
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  • 11,533 POSTS
That is a vacuum source problem. Look for the small line where it comes out of the firewall and should go to a resevoir. Look for cracks or other small leaks in the line.Also look at the line from resevoir to the engine to be sure it is ok. If there is a check valve in the feed line see if it is working properly
Aug 15, 2008 at 4:51 PM