chirping noise driving me crazy!!

[eldridge58]

I have a 2001 boxster s that has an annoying chirping noise which seems to be coming from the rear passenger side. It started with one or two chirps upon start up and then would go away. Then it progressed to a few chirps usually 0-25mph. Now it chirps even at idle and speeds up as speed increases. I considered AOS but i replaced it maybe 6 months ago and i looked around everything seems fine, also loosened oil cap to see if chirp would stop and it didn't. one thing i did discover is when a/c is turned on chirp is constant, then you turn a/c off it goes back to a slow chirp. does that mean bad a/c compressor? cold air is still coming out though. also replaced belt and water pump by porsche dealer maybe 5 months ago. Anyone with some suggestions would be greatly appreciated. i need to get rid of this bird!!