I came across the following Mosfet circuit, but am unfamiliar with the Drain, Gate & Source connections; which is which? Can anyone out there, shed some light on this?
This circuit has a float switch (not visible in drawing)
Edit: You mentioned that "The P channel (M1) will have the source going to +V" and then later, "M1's source goes to the load which is the LED and the fuel control valve."
If the first statement is correct, then by inference M1's Drain actually goes to the load, which are the LED and the fuel control valve.