One way to look in there is by removing the windshield plenum - but totally not worth the effort just for a leaf or something. I replaced my broken plenum and found a leaf in there and that explained the noise. A month later the noise was back. I suppose you can dismantle the dash and pull the blower out.

 

No, Im not going that route either for a leaf....lol

I know its not a leaf cause before I drive any of my vehicles I start them and let them run for abit before I get in them and drive and the A/C is always off at start up. Once started you here the sound after the high idle at initial start-up....

 

Im not sure what my next option is..the sound almost has a rythm to it. Like someone playing " TAPs" on a snare drum....its the weirdest thing. Several people have asked my about it as well...dunno. I guess I'll drive it till she blows

 

Mine comes and goes, it will be quiet and then I hit a bump and it starts up. Normally I turn the fan as high as it will go and then it goes quiet and will be happy until the next bump. Next time turn the fan off and see if it goes away, or turn the fan up high.

 

The sounds is there whether the fan is on or off.....like I said, its a mystery to me...lol