@sj
So, your 24V is with the voltage adj at one extreme?
So, you don't have the wire from this pump? It's kinda important that I know what the polarity is. If you have the wire from the pump I have, all you have to do is plug it into an OEM controller and measure the voltage.
@anybody
I can't make heads or tails with the reverse engineering of the pump. The hall sensor has be baffled. All three lead sensors have a +V, -V and output. That output could be "programmable", open drain or open collector that I can find.
If the hall sensor had inverted outputs with a single power source, then maybe. e.g. V+, OutA, OutB or GNG, OutA or OUTB like a ULN2003 chip has, then maybe. Something where an external pull-up powers the chip. Otherwise I'm stumped.
My meter needs batteries. If the solder blob FET is good, it might shed some light.
4 lead sensor can offer a lot more options.