There can be a number of reasons for this, older cars don’t have a cabin filter and all the dirt and dust collects on the evaporator core, that gets wet and wow a bad smell, this is very hard to fix as it is hard to get to the evaporator core to clean it. But there are a few products to help with this. Most cars today have a filter to stop all this dirt from collecting on the core. If this is not replaced when it’s dirty it can cause a smell as well.
#smell #a/c #filter