Garmin G3X - 10.4.3 Unit Installation; 10.4.4 Wiring

190-01115-01 G3X™/G3X Touch™ Avionics Installation Manual
Rev. AV Page 10-3
10.4.3 Unit Installation
Fabrication of a wiring harness is required. Sound mechanical and electrical methods and practices are
recommended for installation of the GMC 305. Refer to Section 2.3
for wiring considerations, and to
Section 23.5
for pinouts.
1. Drill holes in panel to locate nut plates and LRU (see Figure 10-5
, Figure 10-3, and Figure 10-4).
2. Install nut plates using flush-mount rivets.
3. Hold the unit flush with the instrument panel.
4. Install the four mounting screws (Installation Kit 010-12034-00) through the four mounting holes
in the GMC 305.
5. Use a 3/32” hex drive tool to turn each of the four mounting screws clockwise until tight
(10 in-lbs).
CAUTION
To remove the GMC from the instrument panel, turn each of the two pawl latches
counterclockwise. After initially breaking the pawl latch loose, continue to loosen while
not exceeding 15 in-lbs of torque.
10.4.4 Wiring
The 15 pin connector, pins, and backshell supplied in the GMC 305 installation kit are used to add wiring
for the GMC 305.
It is recommended that a 2 Amp fuse or circuit breaker be used to supply power to the GMC 305
(Figure 24-1.7
). Backup power is optional.
The GMC 305 is connected through RS-232 to any GDU™ 37X/4XX display (Figure 24-1.7
). The
selected GDU RS-232 channel must be configured for “Garmin Instrument Data”.
If the installation includes a Garmin integrated autopilot using GSA 28 servos, the GMC 305 installation
also includes an RS-232 connection to the GSA 28 roll servo (Figure 24-1.7
). GMC 305 RS-232 channel 1
must be connected to any one of the 3 available RS-232 channels on one of the GDU 37X/4XX units. The
GMC 305 RS-232 channel 2 must be connected to the GSA 28 roll servo RS-232 channel 1 if this roll
servo is installed.
For installations using a non-Garmin autopilot with a GMC 305 controller, refer to Figure 24-2.25
.