I use a C300 W204 2010, I got it last year as a used product, however, when I turn off the car, the fan runs for a few seconds or about 2 minutes before it goes off. It came with a bad battery and I got a new battery about 5 months ago. Now the battery drains once I use it for a short distance and requires to be jump-started from time to time. I checked the alternator and it is fine. Kindly advise if it is normal for the fan to run after the car is off and also if that might be what is draining my battery?