When the weather outside got hot, I had my vent blowing (not the air conditioner) and there was a very bad smell. So bad that I got nauseated. I took it to the dealership 4 times for this same odor problem from the vent and no one knows what the smell is, nor how to get rid of it. They ran it through an Ozone cleaning system and deodorized the A/C unit 3 times (even though I don’t think it’s the A/C). There is also a loud buzzing sound that’s coming from the driver’s side window. This happens when the wind blows on it. There is also a clicking sound that I think is coming from the passenger’s side which is near either the seat belt or the rear passenger’s side door. What do you suggest?
It is possible that your evaporator may have fungus growing on and it’s so thick that the cleaners you are running are of no use. In extreme cases, the evaporator will actually need to be replaced in order to get rid of the foul smells coming from its growth.
This issue all starts with an improperly functioning evaporator drain tube. If this drain tube gets clogged, it will allow moisture to remain inside the dash near the evaporator. Due to the fact that this is a dark, cold, damp place, the likelihood of having mold growth is high.
It is also possible that you may have a small rodent that died inside your dash somewhere. To determine this for sure, a telescoping inspection camera may be required. This camera will be inserted into the dash vents and is able to bend around corners to see things that you could not see with your eyes alone. If dead animals are found inside the dash, it may be necessary to remove the whole dash in order to remove them. If this is the case, ensure this job gets performed by a qualified professional to ensure everything goes back together properly.
If you decide that you need help with this, feel free to contact a certified mechanic who can pinpoint the smell you are experiencing and make the necessary fixes to get the odor out.