Wondering if anyone else has noticed a fairly noticeable whistle at freeway speeds that goes away when the HVAC system is turned on. I am experiencing this on my vehicle (an '03 2500 QC)... the whistle is almost always present at freeway speeds but will go away completely if I turn on the ventilation system (A/C, vent, heater, or whatever) to any speed. (It takes about 5 seconds for the noise to go away, but when it does it's gone instantly, almost like a switch). If I turn the HVAC system off then the noise immediately reappears. Seems like the whistle must be near or in the cowl air intake, and when the vent system is turned on the pressure in the intake is lowered a bit and stops the whistle - or at least that's my theory.

Anyone else noticed this?

 

When I first bought my truck I noticed the same sort of sound but the wind noise coming from the driver door overpowered it. This is my first Dodge so I thought it was normal. I always keep the fan on low speed now, I like the air flow anyways. My main beef was when my door leaked whenever it rained which drove me nuts so I took it in. My door no longer leaks and the wind noise is gone except when there is a cross wind. I have never turned my fan off since but I will check again.

 

Check out this TSB: 23-018-03.

http://www.turbodieselregister.com/m.../tsb/03tsb.htm

It talks about a whistle when the blower is turned on but it might be something to look into to and ask your dealer about. Also like Gasman said, perhaps the door is misaligned just enough to cause the whistle. Just two suggestions and I hope you can get it solved.

 

Well, I finally did get it solved. After some more troubleshooting things seemed to point more and more to something within the HVAC system itself. My guess was that there was a slight leak at what DC calls the 'blend air door' in the air-handling part of the HVAC system (I believe there are two, controlling recirc and hot/cold air mix). I took the vehicle to a dealer and asked that they perform the electronic self-calibration routine required after these parts are replaced or serviced (you need a DC scan tool to do this - it runs the doors back and forth and resets the limit points). They performed the procedure (took all of 2 minutes) and it fixed the problem completely. Whew... would have been a real bear to fix if I (or they) had to tear the HVAC system apart. Love those electronic fixes...

Anyway, hope this helps someone else...

 

I have this same noise and I want to thank you for having this information handy.

 

I too had this noise at freeway speeds, took to dealer and they replaced the blend door something about the factory door did not have the right gaskets on it compared to the replacement door. sure is alot nicer without that noise,

 

Same problem with me too. My 2003 2500 has a noticable squeal when I have the HVAC system **** in the full counterclockwise recirc mode. Other modes, no squeal. I think I need to show your info to my dealer. I have been hesitant totake it in as i have nightmares of them tearing my HVAC system apart only to have a worse problem later from tampering. I guess i dont have alot of faith in techs paid flat rate...Personal problem I know!

 

I don't blame you for wanting to avoid having someone go in there...

Have your dealer try recalibrating the blend air door limits as described earlier in the thread. Can be done in a few minutes with no disassembly whatsoever. It might help and at the very least it can't hurt...