I have a 2013 mini cooper. sometimes I get hot air blowing when it's cool outside and the heater & AC are off. AC works fine, heater works fine. Feels like the heater is on when it's off. I brought to the dealer, they could not recreate the problem but told me they need to replace the "heater control unit". Any Ideas?

 

I never run fan without A/C, most other cars don't provide hot air in that situation. But if it works fine with A/C it's not something I would worry about.