Mate has had an auto electrician look at the diagrams and he says ..
1) Solenoid is there to RELEASE air when the ride is too high .. ie after removing a heavy load the car will sit high, this lets air out to drop the suspension, controlled by sensor
2) Pump is there to pump up suspension and is controlled by sensor (which we knew).
Apply 12V across pins A & C (A -ve C +ve) should give a "click" from the solenoid
Apply 12V across pins B & D (B +ve D -ve) pump should run.
Done this to the pump gstylebaby supplied and it works exactly like that so is NOT faulty. Done to the original pump and it does exactly the same, so it ain't faulty either...

So, its either the sensor or a break in the wires he thinks ....
To get me mobile I have wired a 12 volt supply through a switch to pins B & D and can now switch the pump on and off manually. I'm using a length of cane to "measure" the rear wheel arch height when loaded and "adjusted" .. if it goes too high when "unloaded" I pop off the airline to deflate the system then pump back up.
Hate bodges like that but until I can get hold of a sensor, and pm's have been sent to those who have offered, it gets me mobile...
