cat shat in my AC? (or just nasty motor brushes)

[aaronhoy]

So when I first bought my E36, the AC didn't work because the blower motor wouldn't cut on (save your breath, it wasn't the "resistor pack"). Two brand new motor brushes later and everything's working fine.... except if the car has been sitting in the heat for a while and then I get in and turn on the AC, the air coming out smells horrible. I'm seriously considering the idea that some animal left droppings in there. Or is it maybe the new motor brushes? I ordered generic graphite brushes from mcmaster-carr, so they aren't specifically meant to be in an air vent system, so maybe as they wear they just smell bad and you aren't supposed to put them on something that you care how it smells?
Any ideas here?

[strad]

Did you make sure the airbox was squeaky clean before you put the motor back in? On my E34 there was a lot of crap (mostly leaves) at the bottom, including some that had fallen on the resistor and caught on fire (:eek:).

[aaronhoy]

I tried to vacuum out what I could, but there was some stuff that would have been a real pain to reach so I left it. It was like you said though, leaves and stuff. I have a hard time imagining that stuff smelling like...this.

[Brent 930]

It can be cleaned out, and then install a new filter. You should be good then.

[flyfishvt]

Youve got decaying vegitation in your a/c system. Of course its going to smell. Add a little moisture from the a/c condensing the it out of the air and bingo. Instant odor. The sun just bakes it like a casserole. You need to clean it out completely.