2013 buick verano a/c motor blower

What is your question?

motor speed goes up or down by itself from time to time I need to bring speed up to keep down temp. we average 80 deg. temp. in miami, motor will have a humming noise on high speed

What makes this problem better or worse?

at any giving time, cool, hot.

How long has your 2013 Buick Verano had this problem?

about a month