Bad Musty odor comming from A/C <FIXED>

As long as I was asking for help today I figured I would share a solution I found for the bad smells in my Saab 9-3.

I had a horrible musty moldy smell coming from the a/c. It would really mess with my allergies. After searching the forums I started by sealing off the exterior air filter housing and replacing the filter. That wasn't the problem. I pulled out the a/c vents in the cabin and sprayed disinfectant down into the system to clean the a/c vents. That didn't fix it either.

I was cleaning the back windows one day and smelled the same odor coming from the headliner. I dropped the headliner, that was a long process but it was well worth it, expecting to find a loose drain tube from the sunroof drain. Nope. All was good but when I dropped the headliner I could really smell the odor. So I knew I was in the right area finally. I tested the sunroof drain lines to see if they were clogged by pouring water through them. They all drained properly.

Finally I took some disinfectant. I diluted down some Mr. Clean concentrated disinfectant and put it in a lab type squeeze squirt bottle and flushed all four sunroof drain lines with the Mr. Clean solution. I turned on the a/c after and it smelled just like Mr. Clean coming from the a/c vents. The musty smell was gone. After a bit, a few weeks, the odor started to resurface. I noticed it mainly after it had rained on the car. So I made another bottle of the solution and flushed all four lines again. Smell gone again. So I made that a weekly maintenance item and did it every weekend for a month to clean the out the drain lines.

After the persistent flushing the odor has been gone and has been gone for almost 6 months now. It still smells clean no musty odor or Mr. Clean smell and I am confident that I have solved the mystery of the musty a/c odor in my car.

The only thing I can't understand is how the two systems are connected to each other. I know that that sunroof drain system and the a/c system are separate systems so how did the musty odor from the sunroof drain lines impact the a/c system so adversely.