Whistling under hood

[05Yukon23]

I had same issue on my tahoe.. Thought it was my cold air intake too.. seemed to only happen at idle, and at lower temps. YOur right - it IS the P/S pump, and there is a TSB on this issue.. but trying to find it..

---------- Post added at 09:16 PM ---------- Previous post was at 09:05 PM ----------

ps. I didnt do anything to mine... and it comes and goes.. 160k miles....

---------- Post added at 09:22 PM ---------- Previous post was at 09:16 PM ----------

looks like its on NNBS too
#06-02-32-010A: Power Steering High Pitched Whistle Noise Heard in Any Gear with Vehicle Warm (No Fix Available at This Time) - (May 22, 2007)

That kinda sucks. It's annoying when I try to take great care of maintenance and have that stupid sound coming from under the hood. Maybe a new PS pump will fix it. I was told that because of the way they go on, replacing the pulley alone won't solve anything.