[khurmit]

Does anybody know the physical location of part number 4 on the attached diagram?

I have been hunting around in the engine bay for a while now. Its looks as though it should be connected to the lower pipe coming out from the bulkhead (which heads down the passenger side towards the radiator) and should be located somewhere near/under the power steering fluid reservoir, but in reality that pipe only leads to the radiator/gearbox oil heat exchanger, and not the strange looking contraption you can half see at the bottom of the picture (not sure what it is as not numbered).

Any one know of any other pipes that come out from the bulkhead?

To give a bit of background, my cabin heater isn't working and BMW say it's due to a faulty Heater Control Valve. I want to remove and test prior to ordering the part.