The M2 sends a low voltage 12-24v to that Siemans auxiliary contactor. That coil pulls in and powers your pump. The Rainbird will work the same way,...
Without seeing it myself, where that 12v signal is being sent, probably auxiliary contactor poles, need to send 12v from Rainbird to same poles. That...
2014 6.7 here. Tow dump trailers, equipment and a 26' boat regularly. Motor is deleted, I have a filter to catch the bs if fuel pump goes. Trying to...