I live in S FL, so my ac is on pretty much every day in my truck. The fan definitely makes a little bit of noise, almost like a little ticking sound. I have tried lubing it with silicone spray, also tried WD. My next thought is to dry some dry graphite because the noise always comes back in a day or two. I removed the whole blower motor (three screws on mine and it drops right out), cleaned the fins (you might want to check for debris in yours), but the noise always comes back. I don't see any way to replace the brushes or bearings, you might have to replace the whole blower if it bothers you. I'm going to let mine run until it stops working.
88 4Runner - 22re - 181k | 4.88's | Aussie (R) | 33x10.50" BFG KM2 | FROR Front Bumper | Custom Rear Bumper | Warn XD9000i