On my '82 Nissan Sentra, if I didn't turn off the A/C, it wouldn't make it up a hill! Small cars have come a long way...

 

That's the way Mini designed the HAV system. It's common on a lot of other cars as well. The A/C light comes on when Auto is selected as the A/C is used for cooling and de-humidifying if required. Don't forget, the green light on the A/C button just means the A/C system is on and available. It doesn't mean the actual A/C compressor is running all the time.

 

Auto is cool. But Max is cooler.