1. You could have some trash like leaves or something inside the blower case. Its easy to unbolt the blower motor from under the dash i would try that and peek inside the case and make sure there isn't anything in there.
2. There is a TSB for a little ticking sound on blower motors. There's an updated sound sheild thats available that bolts to the blower motor to basically help quiet it down. If your out of warranty you can still buy the sheild and the clips.
I did that and it was quiet for a while. Recently it's gotten noisier again - I'm wondering if I might have stuff in it. Have to find some free time to go to the parking garage at work and tear it apart.
Yea I would remove the blower fan and just clean out all the leaves and shit thats in there. Since we don't have in cabin microfilters (Fronties do have them thought i'd point that out) alot of shit can get into the blower. Watch out for dead rodents seriously.
i dont know i have a button on mine for the air filter. but when i have it on defrost and floor the light goes off. thanx tho yesterday it just quit doing it. i'll tear it apart when it gets a little warmer