ForumLeech
Member
My 2014 B250e makes noises in the front end of the car while it's in the garage with no key inserted. It starts with a strong click followed by the sound of liquid squirting through tubes and 45 seconds of continuous whirring noise like a small electric motor is running. I understand one of the triggers is a button, immediately left of the E/S button on the dash, for enabling climate control while the car is off and unattended. The button lights up blue or red. Turning off this button helped a lot but it still happens occasionally. Today I heard the noise after I disconnected the charger. A couple hours later it made the noise about a minute after I opened the driver door to release the hood. Does anybody know what all the triggers are for this noise and what is being accomplished? I am guessing it comes from a thermal management system used by the main lithium ion battery and climate control system but it doesn't seem necessary under all circumstances. Why would unplugging the charger cause the thermal management to come on? Also, I noticed the traditional 12V lead-acid battery under the hood shows 14.3V on a multimeter during the noise events and drops down to 12.3V when the car is silent. It's charging the 12V battery during the noise like a running gasoline vehicle would.
