Hello, I have been having a smelly problem, everytime I turn my AC on after my car has been sitting for a while the air that first comes out stinks really bad then it will disappear but the smell is really bad/nasty/embarrasing, any idea of what could be causing this? :o

It's the moisture in the vent passages. Add a little organic matter (pollen, and such), and you can have a jungle (bacteria and fungus) in there. You can try spraying some Lysol or such. Also, verify that the condensate is freely dripping from the drain hose (near the front tire on the passenger side).

I've had similar experiences with a few vehicles. I just turn the car on, the AC on, set it to recirculate the inside air, and finally spray the hell out of the interior with a air sanitizer. Leave it like that for a while and it should help out.

Believe it or not, some said the OEM wipers gave off an odor too.

Read this thread "Musty smell from cowling"
http://www.chevymalibuforum.com/forums/showthread.php?t=1893

If the smell isn't the wipers and it is coming from the a/c vents, your dealer can enable the after blow module. I know this works for 2008 and up and the air will dry out the case so that no mold or mildew will grow. I did it on my 2010.

Afterblow Enabling
The afterblow mode can be enabled using the scan tool. The afterblow mode allows the blower motor to operate after the engine has been turned off. This operation of the blower motor dries the evaporator core, which reduces the amount of microbial growth which can create undesirable odors.

Use the following procedure in order to enable the afterblow mode:

Connect the Scan Tool.
Turn ON the ignition, with the engine OFF.
Select HVAC Module.
Select HVAC Systems Manual.
Select BCM.
Select Module Setup.
Select Afterblow Option.
Upon selecting the afterblow option a asterix will appear next to the word afterblow meaning the function is enabled.
Select the save option in the lower left of the screen.
When afterblow has been enabled by the scan tool the blower motor will operate for 2 minutes 30 seconds to 4 minutes after the engine has been in Key OFF for 30 minutes.

The following conditions must be met for the HVAC module to operate the afterblow:

• The outside air temperature must be at least 21°C (70°F).

• The A/C compressor must have operated during the latest key cycle.

• The engine must be turned off for at least 30 minutes.

• The system voltage must be at least 12 volts.

So with the engine off it continues to run for 2-4 minutes...or it waits for engine off for 30 minutes, then runs for 2-4 minutes? Isn't that going to drain battery life for the long run?

I just sprayed some lysol in the intake vent under the windshield outside with the A/C on max...it lasted for about 2 months and now the smell is gradually coming back.

You can get specially formulated sprays at auto parts stores that will kill the smell. Sometimes household chemicals can react with the metal in the internal passages of the AC and cause damage to them. To kill the smell the spray has to get inside the evaporator where the mildew is located.

Bill

I just enabled the afterblow module on mine since I could start to smell some mold. Easy for the dealer to do, it took me 2 minutes to enable it with the tech II. I wish the factory would just enable them no matter what and save the trouble. The blower motor doesn't run long enough to drain the battery, and there is enough battery rundown protection to keep it from doing that. I haven't had any problems since. Also, some older vehicles aren't equipped with the option, but there is dealer installed modules for the mold smell issue.

To prevent this from happening, turn your a/c off and onto fan only about .5 to a mile before you return home. This is dry out your a/c filter and will cause it from molding or from that moldy smell.

That's what I do ;)

Those that have had the dealer enable the afterblow module, is this covered by the warranty?

Oops, I'm surprised that no one responded yet. The afterblow enable is part of TSB #99-01-39-004C. http://blog.corvettecentral.com/2010/03/hvac-odor-technical-service-bulletin/. If you have a legitimate concern, the fix will be covered by the bumper-to-bumper warranty.

And, welcome to the forum and hope to see you around.:)