Subject: | High Pitch Whistle When HVAC Blower Fan is on High and Full Floor Mode |
Models: |
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in the PI.
Some customer may report a high pitch whistle or air rushing sound when the HVAC system is set to full floor and the blower fan is set on high. Furthermore, the customer may report the noise comes and goes with the fan speed. One possible cause of the noise could be the defogger vent assembly is not completely seated into the HVAC plenum.
If all diagnostic procedures have been exhausted and the noise remains, the defogger vent assembly should be suspected. The following steps will need to be completed to correct the noise.
Note: The system should be tested once steps 4, 5 and 6 have been completed to ensure the complaint is corrected and the center defogger outlet vent has not become unseated.
Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
(2001-2005 Chevrolet Venture) and (2001-2004 Oldsmobile Silhouette) and (2001-2005 Pontiac Montana)