whistling noise when re-circulate is on

[rxis]

I have a whistling noise in an 07 YD when re-circulate is on while the a/c is running. It started after a car wash yesterday.

Any ideas?

 

[Modded]

Thats odd. I do know when my recirculate is on the A/C system gets louder, but no whistles.
Did you track to see if its coming out of a particular vent?

 

[ScottL4619]

Here you go...found here (you can signup if you want to see the pictures): http://www.justanswer.com/questions/22006-06-chevy-tahoe-v8-the-front-ac-defrost-and-heat-will-not


Condition

Some customers may comment on a whistle sound when the blower motor is on and the heating, ventilation and air conditioning (HVAC) control is put into recirculation mode. Other customers may comment that the blower motor stalls out or vibrates or that a "sticky" noise is present during air recirculation door operation.
Cause

The adhesive foam used on the air recirculation door (air inlet valve) may not be properly secured, causing some of the foam to contact other HVAC components. The foam could potentially come in contact with the blower motor fan and/or the foam may stick to the inner HVAC case walls, causing the door to stick or hang up.
Correction

Locate the loose foam and reattach the adhesive foam to the recirculation door using the steps below:

1. Remove two screws from the right side HVAC sound insulator panel (hush panel).
2. Drop down the insulator panel.
3. Disconnect the electrical connector from the blower motor.
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4. Unlock the blower motor retaining tab, referring to graphic above, by pulling the retaining tab (1) down while turning the blower motor counterclockwise in order to disengage the blower motor from the HVAC case.
5. Remove the blower motor.
6. Locate the partially loose foam from inside the HVAC case with a flashlight.

Important: It may be necessary to cycle the air inlet door by placing the ignition switch into the run position and selecting the buttons on the HVAC control head from outside air to recirculation mode.
7. If the foam is damaged, refer to Recirculation Door Replacement (Delphi) or Air Inlet Assembly Replacement in SI and do not proceed with the following steps.
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8. If the foam is not damaged, reach into the HVAC case and reattach the loose foam to the air recirculation door by using your hand to apply firm pressure to the foam and door.
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Important: The recirculation door should have foam on both sides of the door to seal properly. Refer to the above graphic.
9. Confirm that the foam has been secured to the door by cycling between recirculation and outside air positions on the control head three times. Once cycled then observe from the blower motor opening in the HVAC case to see if the foam is secure. Refer to the graphic above.

Tip
If the foam is not secure, you may apply a small amount of 3MTM Super 77 Spray Adhesive, or equivalent, to an acid brush and apply the adhesive to the door and reattach the loose foam.
10. Install the blower motor into the HVAC case by turning the blower assembly clockwise until the retaining tab locks into place.
11. Connect the electrical connector to the blower motor.
12. Reinstall the insulator panel and two screws.

Tighten
Tighten the screws to 1.6 N·m (14 lb in).
13. Verify that the customer's concern has been fixed.


Read more: 06 Chevy Tahoe V8: The front AC, Defrost and hea... - JustAnswer http://www.justanswer.com/questions...nt-ac-defrost-and-heat-will-not#ixzz0wguCm8Ws

 

[rxis]

It wasn't coming from a particular vent. The sound went away today. I washed it again and it didn't come back.