Hi, my wifes 330Ci's power steering wont function, so heavy to steer.

poss bad rack and pinion or pump is going out seek a diag and est

Check the power steering reservior if your low on fluid or it could be a bad rack and pinion or power steering pump or a power steering hose leak. If you can have the car lifted on a hosit and inspected you can check if you have any power steering leaks.