what can cause a hissing, air leaking, sound from under the dashboard?

2007 DODGE TRUCK
116,000 MILES
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BRETTWOOD67
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hissing or air leaking sound from under the dash on driver side, changes pitch sound when i turn the steering wheel or step on the break petal.
Sep 8, 2011 at 10:33 PM
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PROMECHANIC
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  • 536 POSTS
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It sounds like you either have a brake booster that is leaking or you might have some vacuum lines under the dash that have holes rubbed in them. The booster is connected to the brake pedal so anytime you press on the brakes you will notice a noise if it is bad.
Sep 8, 2011 at 10:39 PM
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SATURNTECH9
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If your hearing it while stepping on the brake pedal sounds like you have a leaking brake booster.If you get a hand vacuum pump you can rent one at auto zone and see if it leaks.
Sep 8, 2011 at 10:40 PM
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