Buzzing Type Sound?

I’m unable to upload the video for some reason, but I just went outside to grab something out of my ‘18 and I thought I could hear a weird buzzing noise in the distance (midnight here).

I went next to my back right tire and it was louder, coming from under the truck.

I haven’t driven in maybe 4 hours.

Went inside to grab my keys to start it up and drive around the block to try and see if something was wrong and as soon as I got back outside with my keys there was no noise at all.

Anyone experience this? Sorry I have no media. Literally sounds like a really old fluorescent lamp ballast on its way out if I had to compare

 

Evap check. 100% normal. Owners manual.

 

I’ve never heard this with my last two Tacomas over the last 6 years. Must just be coincidence I’ve never been outside while it was happening.

 

Yep, I think manual state’s something like 5 hours after shut off.

 

My 2007 Corolla had it. The system waits for about 4 hours to cycle the evaporator system.

 

Crazy I haven’t heard it before! Thanks everyone. Sorry for the fire drill