Got a 2012 used Grand Caravan with heater/AC blower noise. Low or high setting still same noise. High pitch ringing doesn't change with speed of van or radio on/off. Dealer wants $100 to trouble shoot. Is this a common problem anyone heard of? If so is it DIY or repair shop fix?

 

I have had issues with the blower motors making noise. They are very easy to install if you would like to do it yourself.