Garmin G3X Pilot's Manual page 358

AFCS
Changing the selected heading (GMC 305):
1) From the PFD Page (one display) or PFD (two display), press the HDG
Softkey (if necessary). The Heading Box is highlighted.
2) Turn the FMS Joystick to select the desired heading. The Selected Heading
is shown to the left of the HSI.
3) Press the HDG Key on the GMC 305 to activate HDG Mode
Holding the CWS Button (if equipped) and hand-flying the aircraft does not
change the Selected Heading. The autopilot guides the aircraft back to the
Selected Heading upon release of the CWS Button.
Turns are commanded in the same direction as Selected Heading Bug
movement, even if the Bug is turned more than 180˚ from the present heading
(e.g., a 270˚ turn to the right). However, Selected Heading changes of more
than 330˚ at a time result in turn reversals.
336
Heading Mode Annunciation
Garmin G3X Pilot's Guide 190-01115-00 Rev. K