I'm impressed with the simplicity of this device. The only thing the PCB does is to turn off the device off if it has not been used in a while (the pump was not used). Everything else is directly wired.

My original drawing is attached - I was making it while I traced the cables. I'll add a cleaned up version soon.

Cables/wires: b = blue, bk=black, o=orange, r=red

T,M,B are the top, mid, and bottom pins of switches, respectively.

From what I can tell, the PCB is very basic. It consists of an AC-DC down-converter to power a microcontroller that can measure if the button is pressed or the pump is running and actuate a relays to turn the entire device on and off.