Buzzing Sound | Left Side of Engine Compartment

I was reading up on how to properly hook up a small refrigerator to my 2014 Leaf.
https://www.mynissanleaf.com/viewtopic.php?t=25623

While at it, II decided to check the voltage on the front 12v battery. That was fine. But then I noticed a constant buzzing sound from the left side of the engine compartment. At first I thought it had something to do with the refrigerator. but, the sound continues even when the refrigerator is disconnected.

In fact, the sound is there anytime the car is ON. Most probably, this has been going on for a LONG time. I just never noticed it before, because I never opened the hood while the car was on.

QUESTION: Do all Leafs make this buzzing sound (only audible in the engine compartment) when ON? Is this normal?

Townsend said:

QUESTION: Do all Leafs make this buzzing sound (only audible in the engine compartment) when ON? Is this normal?

Click to expand...

Short answer: no, that's not normal.
Without some additional localization of the sound (is it high or low frequency?) it could be electrical (likely) or mechanical.