Power Steering, how it works?

[SVX JAZZ]

My power steering has been working well for the past week since I fooled around with the sensor near the power steering pump. What does this sensor do? No dash lights lit up when I un-plugged it. Mine is a 92 with speed sensitive steering. It has never seemed that speed "sensitive" though. How does the speed sensitive steering work? Does the pump vary it's pressure?

I would like to know why the binding in my steering simply went away. I do not belive it is a rack problem now. Racks don't usually just get better.

Thanks!!!!!