Whistling sound in cabin varies with AC fan speed. How to reach ducting? on 2005 Chevrolet Silverado 2500 HD

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Air noise (whine) Suspect air leak in system. Fan just replaced due to electrical short. Noise was there before and is as bad or worse now. Annoying. How hard is it to get to the air distribution plumbing? Getting 6 hour or more estimate from dealer.
(1) Answer
It sounds like you have a blend door problem in your Climate Control System. This will need to be inspected by a good Climate Control Diagnostic person.
here is an article that we at have constructed to help you with this process.

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