Air Conditioner issue on 2006 Pontiac Grand Prix

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I'm having two problems with the A/C on my GP. First, there is always a musty/moldy smell when I first start it up after the air conditioner has been running.

Also, the re-circulation light keeps turning off and on - once per second or so - it essentially blinks.

Any help appreciated
(1) Answer
The musty odor is from bacteria growing on the a/c evaporator, this is not uncommon. Make sure the drain on the evaporator is clear and operating properly. You can buy some spray that will help to kill this bacteria, check with you local parts store. As for the blinking light, this is indicating a fault in the system, you will need to read the diagnostic trouble codes and then diagnose the problem.