I noticed a sound coming from under the hood while I have the key on but the Jeep isn't running. My friend asked if there was a hard drive under the hood. It's a noise coming from the passenger side of the throttle body. I'm guessing the throttle is not cable activated like my TJ so is this the throttle control? Also why is it making noise? I'm also guessing it's normal because the Jeep is working properly.

 

Could be your fan.

 

I noticed the same thing also with mine, freaked me out at first, I dont know what it is but it sounds like the starter, or fan

 

It's coming from a black box attached to the passenger side of the throttle body. If you put your hand on it you feel it vibrate as it makes its sound.