Chirping sound - but not belt or tensioner
 

Need some opinions on a sound, I've recorded for you.... A repetitive chirping sound started coming from (I think) the serpentine belt area. Before someone suggests the obvious: I replaced both the tensioner pulley and the serpentine belt. This did not solve the problem. It also doesn't sound like a power steering problem to me, and the sound seems to be coming from lower.

It's easier to hear from inside the car, while under load and going down the road. I hear it most when slowing down. When the car is in park, I can hear it best when the fan cycles off (not 'on'), as you'll hear in the video. Also, when I'm going down the road, and turn my A/C off, it seems a little louder. I'm waiting for a stethoscope in the mail, to help pinpoint... but in the meantime

I'm thinking maybe something's wrong with the A/C compressor, but wouldn't it be louder when the fan is ON, not OFF? I don't know.

I'm hoping someone else recognizes the sound, and has some other options. Maybe a water pump issue? I don't know what, if any sound, that might make. I doubt it's the timing chain, right? Those don't go bad very often.

Here's the video:

I should add that I spun all the pulleys when I had the belt off, and didn't notice any issues or sounds. So, that also has me a little stumped...

From beneath car
 

Here you go... Apologies, it took me a second, before I realized I was pointing my camera at the wrong pulleys. Also, This morning, I double-checked the pulleys. I pulled the belt off and spun the A/C pulley by hand. I think I could hear a slight roughness in there. So, maybe it's that bearing starting to wear out after 125k miles.

Yep! Turned out to be the bearing in the pulley. I checked with a stethoscope to confirm it. Once I got it off, it sounded like a dirty coffee grinder.

I replaced both the pulley and clutch this weekend... and video'd it, too! Sometime later this week, I'll post up a video showing the repair!

As promised for future reference... A video of how I replaced it: