My 01 BMW 325i AC Problem

What is your question?

My BMW 325i AC will be working fine, and then all of a sudden start blowing hot air for a while, then goes back to blowing cold air. Any idea what should be replaced? The blower motor seems to work because air keeps coming though, so I am not sure. when it starts blowing hot air, sometimes it seems like there is a slight hum maybe...very low volume.

How long has your 2001 BMW 325i had this problem?

a few days