190-01115-01
G3X/G3X Touch Installation Manual - GMC 305 Installation
Rev. AC
Page 12-2
12.3 General Specifications
See
for power/current specifications, and
for dimension/weight specifications.
12.4 Mounting and Wiring Requirements
12.4.1 Fasteners
The GMC 305 is installed using the four #6-32 threaded cap screws supplied in the GMC 305 installation
kit using a 3/32” hex wrench. The instrument panel may be drilled and tapped for the #6-32 screws, or the
four anchor nuts supplied in the installation kit may be installed using flush-mount rivets.
12.4.2 Panel Cutout Template
can be used as a template when marking the panel for cutout. Dimensions on the figure are to
verify accuracy of printout only, see
for complete cutout dimensions. A .dxf version of the
drawing is also available for download at
www.garmin.com
.
12.4.3 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
for wiring considerations, and to
for pinouts.
1. Drill holes in panel to locate nut plates and LRU (see
,
).
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).
12.4.4 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
(
). Backup power is optional.
The GMC 305 is connected via RS-232 to any GDU 37X/4XX display (
). 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 (
). 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
.
Table 12-4 Contents of Mounting Kit (011-03242-00)
Item
Garmin P/N
Quantity
Nut, Self-Locking, Plate, One Lug, 6-32
210-00104-04
4
Screw, Machine, Panel Mounting, 0.550", Black
211-00169-01
4