A/C Heater Whistling Noise

[ampenergy88]

Does anyone have any suggestions on how to fix the A/C / Heater Whistling Noise that I'm experiencing with my 99 tahoe?Its is so annoying?Its comimg from passenger side vents. All vents are open.
Thanks!:confused2:

 

[PotentialTahoe]

I have the same problem, Does ANYONE know of a fix?

 

[treepete]

does it whistle on all fan settings, or just high?

maybe the mode actuator stuck and its whistling and you can only hear it through the passenger vents?

 

[ampenergy88]

I got mine fixed at the dealership,They used some black sealant on the lower Heater core box and it fix the problem.They tried to slap a new blower motor in and charge me $305.00. So I hopped in my wifes car and went the the dealership and explained my blower was fine and had them reinstall it.So then they they actually fixed the air leak.
I ended up paying $145.00 for the labor.I wasn't too happy about that.But the problem is now fixed,