Originally Posted by von_flyer
Thank you Michael. So the hat switch does take the signal to ground, true low. I don’t plan on a second trim switch so no GAD27.
I assume the GP1 input is configured in the G3X and displays the trim position.
No, not grounded.
Without the 27, you need 2 relays to send power, in both polarities to the the servo. The RA servo consumes an amp and you hat switch cannot handle that. The 28 goes into bypass mode when shut down and your switches / relays need to handle the full amp in this case. Also, the motor reverses by getting power in different polarities. The 28 is also looking for different polarities, when not in bypass mode.
The relay is typically activated via a low/ground on the hat switch, assuming you feed + on the other side of the relay coils.