2001 Toyota Echo A/C noise

I'm hearing the a/c fan turn in and running while I'm parked, stopped @ a light and stopped in traffic. I first noticed the noise 2 yrs. Ago just slightly and now its louder than before. There's no noise when the "fan" is on without the a/c on. Then there's a slight vibration happening when the a/c itself is turned on and running.
The a/c noise starts off like this: I turn on a/c and a "squeky" like noise begins followed by hearing the fan turning on and running and then slight vibration. My a/c does work so I do get cool (not cold) air inside cab. When I bought car from original owners back in 10/2004, I took it to Costco to get brand new tires, checked the alinment-good. Then to Maui Toyota dealership to check on
a/c cause I thouught it wasn't cold enough-was cool. They said everything is fine and that the slight vibration coming from the a/c unit was normal. Do I have a big problem brewing?