The ford transit's back battery under the seat (which I thought was just for starting) is automatically turning (probably) something underneath the driver's side door on, even if the engine is off and the key isn't in the ignition.
This makes a running noise similar to that of a fan and then another noise, after which smoke starts coming out and it smells like burnt plastic.
The only way to turn this off is to disconnect the battery.
When the battery is reconnected, I can hear a relay clicking and the noise immediately starts again.
Attached is a video and picture of the component from near which the smoke comes. Can someone tell me what this component is and what the problem could be? Could it be as simple as a faulty relay?
Video: https://1drv.ms/v/s!Agg2m_iROav7gbNbQgqSrzaQkKWsoA?e=PA6fTG
Any help is greatly appreciated!