AAZ Auxiliary pump

[mrnickmuss]

I have just fitted a replacement AAZ and realised that it doesnt have a hole in the flange on the rear of the engine to take a sensor switch for the auxiliary pump.
However I do have a flange on the top of the engine with two holes. I have just bought a new sensor/switch and fitted it and connected it up I have run the engine until the fan kicks then ran it a bit longer.... I then checked to see if the auxiliary pump switches on.... Nothing.... I can feel the pipes are good and hot and I know the pump is working.
My questions are: Should it come on in these conditions?
Also: Is it ok to fit it on top of the engine rather than the back?
Thank you.

[dave friday]

As far as I know the switch should be fitted to the flange on the middle of the head ( where you've fitted it,mines there too )
It won't come on until the water is very hot ( 107 deg c !! )
Mine never comes on even when it's 40 deg c ( in the shade ).

[mrnickmuss]

Thanks I know that with my old engine it was quite often on... but then again it died from over heating!

[dave friday]

I think it might possibly come on if I turned the engine off when the radiator fan comes on ( second stage!).
One thing we've noticed ( on all 3 vehicles ) is that antifreeze brings the coolant temperature down.
Anti cavity ? It says that on the can! (Can we call a plastic container a can? ).