Pronounced hum even when stopped

The other day I was driving home with the radio going, heater blasting, and slush on the road, so I couldn't hear much of anything from the car as I drove. But when I turned into my parking lot and started shutting down the radio and heater, I was surprised to hear a pretty loud hum coming from the front of the car. It wasn't related to the car speed at all; when I came to a complete stop in my parking space, it was still going, sounding just like it had as I was moving.

Unfortunately I didn't have the presence of mind to try just putting the car in neutral or park, but instead simply shut it off. The humming stopped instantly. I turned the car back on, but didn't get any humming.

It seemed to me to be a bit higher pitch than a 60-hz hum.

That was a couple of days ago, and it hasn't happened again.

Has anyone else had anything like this happen?

You may be hearing the climate control system, especially if you have a heatpump-equipped Leaf. It can sound remarkably like an idling gas engine as well.

could be the radio

powersurge said:

could be the radio

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+1
I've heard a similar noise in my Leaf and it turned out to be the radio. I can't remember if the radio had to be ON or if it just happened when the volume was turned all the way down but I chalked it up to all the electronics in the car somehow getting into the radio's amplifier.

The car has speakers that emit a distinctive hum at low speeds for pedestrian warnings. It typically keeps going for 5-10 seconds after you stop moving.

Thank you all for your replies, but it wasn't the radio (I had just shut it off), it wasn't a heat pump (I don't have one), it wasn't the climate control (I had just shut that off, too), and it wasn't the weird pedestrian warning sound (I'm familiar with that).

So, still a mystery.

Could be the coolant pump? It has a hum when running, though usually quiet. A simple test, park the vehicle in front of charger, shut off. No hum? Plug in charger, should activate coolant pump, see if the hum returns?

OP, might be helpful to the community if you tell us which year Leaf you have.

The only weird humming I've had in my 2015 is from the dome light. something about the PWM dimming resonates into a buzz/hum. My fix is to just leave it off most of the time. I suppose I could open it up and calm that down with some hot-glue if I ever get ambitious.

Nubo said:

The only weird humming I've had in my 2015 is from the dome light. something about the PWM dimming resonates into a buzz/hum. My fix is to just leave it off most of the time. I suppose I could open it up and calm that down with some hot-glue if I ever get ambitious.

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I get that on my 2018 as well. Not a huge deal.