Prime up to mischief? Loud fan noise in garage

So I didn't drive the Prime yesterday and it was fully charged from the day before so it was not plugged in. Ambient air temperature around 60f this afternoon. I get by the door to the garage and I hear a racket. I open the door and the noise is coming from the front of my Prime. It sounds like a fan running at top speed. I go around to the driver's side and get in to the car. I am guessing that by some weird circumstance, I have left the car running for two days. However, the dash is not lit up. I start the car up. The usual boot up stuff happens. The fan noise stops. I check the battery level meter and it shows full charge, 33 miles of range. I turn the car off. No fan noise. Any ideas?

Mike

 

Ah Ha!!! And as Homer Simpson says, DOH! Thanks.