AC SMELL- can it be avoided?

[TGCOFTN]

I have two Hummers.........my 2007 has that stinky mold oder coming out with the vents when I first turn it on. I have taken it to the dealership 3 times, and fixing to take it back a 4th time next week. This time I am gonna tell them I dont wont it back until they can fix it. I am getting a little frustrated. They told me it was because of parking it in the garage. The crazy thing is, I have a 2008 with 15,000 miles on it and it dont have that smell. How does a 07 stink, and a 08 dont? makes no sense to me. Also, I have a Volvo S80 thats in the garage, and it dont have that smell. Its only on my 2007.

Another thing I dont understand is, after I park it, and turn the engine off, and remove the key, the air conditionor blower motor will come on all by itself and run for 15 seconds, and go off for 10 minutes, and then come back on for 15 more seconds. It keeps doing that over and over all night long. The dealer said it was normal, but again.........why is it my 2008 H2 dont do that?

I have tried everything, I have sprayed pure air in the vents, left it outside running with the AC on high, and windows down, and everything I do, dont help. So next week, I am gonna tell them to fix it, and I dont wont it back until its fixed. I dont care if they have to replace parts, I cant stand this smell any longer.

Other than that..........I cant say anything bad about them.