noise by PS pump - need help

[emmydotnet]

just noticed some noise coming from the engine bay...some sort of a worn pulley or bearing type of noise. It gets loudest closest to the power steering pump as I try and do a pass (with one ear as close as posible..) from left to right from the front of the car. I did replace the PS pressure hose about a month ago as it was leaking. I am wondering whether the PS fluid got too low affecting the ps pump. This was about 1,000 miles ago.

I am struggling on how to isolate the source of the noise so that I can do whatever repair is needed.

any inputs would be appreciated. It is a 91 560 SEL

thx,
emmy