So I'm rewiring things "my way" and I'm rather confused from my notes.

Two black wires come out of the back of the meter.what is the purpose of
each ground the way you understand it?

I can get the volts and water level to work but when I have both black wires
to ground I cannot get the ground to thermostat housing to fire up the green
LED for the propane setting. Can anyone shed any specific light to help my
confusion.

Shawn