A4 Quattro Sedan L4-2.0L Turbo (CAEB) (2009)
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1. With the engine off, switch the air distribution to only dashboard panel vent mode, set the temperature to LO, and set the blower to level 7. Keep in
mind that adjusting the temperature setting will automatically adjust the blower level in a manual blower override setting. If the blower speed has
changed, then reset the setting to level 7.
2. If the whistling noise does not disappear at Auto and LO, then use the vent door thumb wheels to completely close both center dashboard vents.
^ If the whistling noise is still present with the vents closed, then the vehicle is not affected by Condition 3.
^ If the noise changes significantly or disappears, then the vehicle is affected by Condition 3.
Condition 4 Test
The noise is heard at any temperature setting, regardless of air distribution mode and only when the blower is set to within a range of medium to high.
1. Turn the ignition on. Ensure the left and right temperature settings are still synced and set to LO.
2. Set the system air distribution to panel vent and floor mode (Bi-Level Mode).
3. Slowly change the blower speed from level 6 to level 12 and listen for the whistling noise. If a whistling noise is heard while changing the levels, keep
the blower set to the level in which the noise is heard the loudest.
4. Slowly change the temperature setting from LO to HI while maintaining the same blower speed. You may need to adjust the blower speed back after
adjusting the temperature setting because the blower speed may automatically change while adjusting the temperature setting.
^ If the noise becomes less noticeable or disappears completely, the vehicle exhibits Condition 4.
