We got same thing happened recently!
mine is only a little more than one year's old, and Sumsung, and we called lots of people, and they didn't want to deal with Sumsung. I did check the fan, and it didn't work, and one guy came my house, and said the fan and sensor both didn't work. and he got the parts, and couldn't put it on (Sumsung's very popular problem), and we gave up to fix.