Weird acidic smell from vent

[darkmoon87]

OK. I changed my cabin air filter 2 months ago so it is not that. I even took it out and visually checked it, too. It's not the smell coming from the cabin filter.

It is a very nasty and strong sweat + pee like scent that flows in whenever I turn my vent on. Smell is the same regardless of A/C being on or off (smells a little less bad when AC is on though) and regardless of re-circulation or regular airflow mode.

I have a short ram intake and I took a visual check on the outside of the intake filter and there's nothing. Now I am afraid if there's something dead somewhere inside my engine bay that causes this nasty smell..?

Any insight will be appreciated