Musty odor comes out the vents when running a/c...no diagnosis....not fixed
Smells like horse manure... problems started at 90,000 miles and is not present in winter
I also have a oder coming form the HVAC system and I think I know what it is from. This oder seemed to appear after car washes or rain. In the past if I dump a pail of bleach water over the windshild the oder went away meaning that water was somehow leaking into the HVAC system and the bleach water killed the oder. The problem has gotten so bad now that when it rains and it is cold, near freezing tempatures, when I turn on the heat condensation blows out top vents onto the windshield so bad that I cannot see anything for 5 minuts meaning that there is water in the HVAC system and that oder is from mold/bacteria sitting somewhere in the HVAC system. If it rains and you get the oder you have a leak. Now the problem is to find the leak!