Buzzing noise from rear while vehicle shut off
First post on this forumn. After 30 years of car ownership I recently purchased my first Subaru, a 2011 Forester 2.5X. Nice car, my wife loves it, only has about 1300 miles on it. I went into the garage last night to get something and heard a buzzing noise coming from the rear of the Forester. It had been sitting in the garage turned off for at least 4 hours. The noise kind of reminded me of when the antenna motor on another car I had did not shut off when the car was turned off because the switch had gone bad.
I popped open the rear hatch then lifted and removed the spare tire cover. The noise was coming from the upper left (as I faced the rear of the car) of the area around the spare tire. Right behind the rear passenger seat. There was a plastic cover over where the noise was coming from so I couldn't see what was there. There was room to stick my hand under the bottom of the cover, so I felt around to see if I could determine what was buzzing. But I had not luck. While I was poking around the noise stoppped. It had been making the noise as I walked in the garage. I don't know how long it had been running before I went to the garage but until it stopped, it was probably 3 -5 minutes that I heard it.
I started up the car and took it for a drive to make sure everything was OK. It started and ran fine. When I brought it back there was no noise. I checked it several hours later and there was no noise.
Anyone know what this might be? It was definitely a very consistent electric buzzing noise. I am first of all concerened because it happened and I don't know what it is. I am also concerend because if this continues, it could run the battery down and strand my wife.
My first thought is that might be where the electronic fuel pump might be but I have no idea why it would be running after the car had been turned off four more than 4 hours.
The car is an X model without many options. Allow wheels, auto dimming mirror. No heated seats or anything that should be active while the car is turned off.
I thought I'd try here rather than go to the dealer because it's not very convenient to get there.