Garmin GSD 26 User manual

GSD™26 Installation Instructions
To obtain the best performance and to avoid damage to your boat, install the device according to these
instructions.
Read all installation instructions before proceeding with the installation. If you experience difficulty during the
installation, contact Garmin Product Support.
Important Safety Information
WARNING
See the Important Safety and Product Information guide in the product box for product warnings and other
important information.
You are responsible for the safe and prudent operation of your vessel. Sonar is a tool that enhances your
awareness of the water beneath your boat. It does not relieve you of the responsibility of observing the water
around your boat as you navigate.
CAUTION
Failure to install and maintain this equipment in accordance with these instructions could result in damage or
injury.
Always wear safety goggles, ear protection, and a dust mask when drilling, cutting, or sanding.
NOTICE
When drilling or cutting, always check what is on the opposite side of the surface.
This equipment must be installed by a qualified marine installer.
Transducers
A transducer is required to send and receive a sonar signal from the sounder. Proper transducer selection and
installation are critical to the operation of the device. Because mounting locations vary, see your local Garmin
dealer or contact Garmin Product Support for more information. Go to www.garmin.com/transducers to select a
transducer.
Installation Preparation
NOTICE
This device must be installed according to these instructions to get the best possible performance. If you
experience difficulty with the installation, contact Garmin Product Support.
Because every boat is different, you must carefully plan the GSD 26 sounder installation.
1Select a mounting location.
2Mount the sounder.
3Connect the sounder to the Garmin Marine Network and to power.
4Connect the sounder to the transducer.
TA-2013/325
GUID-CD9D5480-1EC6-4A73-AB59-0037B3321584 v5May 2022

Tools Needed
• Drill
• #8 (5mm) drill bit for mounting surface
• 1 1/4in. (32mm) paddle drill bit or hole saw for mounting surface
• #2 Phillips screwdriver
• 3mm flat screwdriver
• Cable ties (optional)
• Dielectric grease
• Wire cutter
• Wire stripper
• 1in. (24mm) and 19/32in. (15mm) wrenches
• Marine sealant (optional)
Mounting the Sounder
Mounting Location Considerations
• The sounder must be mounted in a location where it cannot be submerged.
• The sounder must be mounted in a location with adequate ventilation where it will not be exposed to extreme
temperatures.
• The sounder should be mounted so that the LEDs are visible.
• The sounder should be mounted so that the power and network cables can be easily connected.
• The sounder should be mounted so that the transducer cable can be connected. If required, transducer
extension cables are available through your Garmin dealer.
Mounting the Device
NOTICE
If you are mounting the bracket on fiberglass with screws, it is recommended to use a countersink bit to drill
a clearance counterbore through only the top gel-coat layer. This will help to avoid any cracking in the gel-coat
layer when the screws are tightened.
Stainless-steel screws may bind when screwed into fiberglass and overtightened. Garmin recommends applying
an anti-seize lubricant to the screws before installing them.
Before you mount the device, you must select a mounting location and determine the mounting hardware
needed for the surface.
NOTE: Mounting hardware is included with the device, but it may not be suitable for the mounting surface.
1Place the device in the mounting location and mark the location of the pilot holes.
2Drill the appropriate pilot hole for one corner of the device.
3Loosely fasten the device to the mounting surface with one corner and examine the other three pilot-hole
marks.
4Mark new pilot-hole locations if necessary, and remove the device from the mounting surface.
5Drill the appropriate pilot holes for the other three marks.
6Secure the device to the mounting location.
2 GSD 26 Installation Instructions

Connecting the Sounder
WARNING
When connecting the power cable, do not remove the in-line fuse holder. To prevent the possibility of injury
or product damage caused by fire or overheating, the appropriate fuse must be in place as indicated in the
product specifications. In addition, connecting the power cable without the appropriate fuse in place will void
the product warranty.
NOTICE
Do not force a cable into its port. Forcing the cable can damage the pins. If the cable is properly aligned, the
cable should connect easily.
Before you connect the sounder to the network, power, and the transducer, you must mount the sounder
(Mounting the Sounder, page2).
1Route the cables using the appropriate tie wraps, fasteners, and sealant to secure the cables along the route
and through any bulkheads or the deck.
2Install the locking rings on the marine network and power cables (Installing Locking Rings on the Cables,
page6).
3Connect the bare-wire end of the power cable to a 12Vdc power source and to ground.
4Apply dielectric grease to the end of the power cable.
5Align the notch on the end of the power cable with the power port on the device, and press the cable into
place.
6Tighten the locking ring.
7Repeat steps 4 and 5 for the network cable, and connect the device to a transducer (Connecting the Device to
a Transducer or Sensor, page3).
8Select an option:
• If your boat is equipped with a GMS 10 network port expander, connect the network cable to an available
port on the GMS 10.
• If your boat is not equipped with a GMS 10 network port expander, connect the network cable directly to
the network port on your chartplotter.
Cable Routing Grommets
When routing cables through your boat, it may be necessary to drill holes to route the cables. Cable routing
grommets can be used to cover cable installation holes. The grommets do not create a waterproof seal. If
necessary, apply a marine sealant after installation to weatherproof around the grommet and the cable. You can
purchase grommets from your Garmin dealer or directly from Garmin at www.garmin.com.
Connecting the Device to a Transducer or Sensor
NOTICE
You must install cord grip plugs in any unused cord grip to make sure water cannot enter the transducer wiring
block area and damage the sounder.
The terminal blocks are not removable.
GSD 26 Installation Instructions 3

Preparing the Cable
1Remove the terminal block lid from the sounder.
2Select an option:
• Feed a sensor cable through the small cord grip , and pull the cable into the terminal block area.
• Feed a transducer cable through one of the large cord grips on the housing, and pull the cable into the
terminal block area.
NOTE: Do not tighten the cord grip.
Connecting the Wires to the Terminal Block
Before you connect the wires, consult the wiring diagrams (Transducer Wiring Diagrams, page6) to select the
proper wiring configuration for your transducer and the wiring tables (Transducer Wire Color Tables, page11)
for specific examples of Garmin wire colors.
1Connect the uninsulated section of each wire to the terminal block using a 3mm flat screwdriver.
2Connect the bare shield wire to one of the two ground posts under the terminal block using a #2 Phillips
screwdriver.
Securing the Wire Connections
1After connecting the wires, use a 24mm (1in.) wrench to tighten the nut around the transducer cable.
When tightened correctly, you should not be able to pull the transducer cable out of the housing.
2Insert a cord grip plug into each unused cord grip.
3Replace and secure the terminal block lid on the sounder with a #2 Phillips screwdriver.
NOTE: The sounder does not operate when the lid is removed.
4 GSD 26 Installation Instructions

Grounding the Sounder
The chassis ground post is located on the exterior of the chassis, adjacent to a corner mounting hole.
1Connect the chassis ground post to the boat water ground circuit.
NOTE: The boat battery ground is an acceptable alternative if your vessel does not have a designated water
ground circuit.
2Mount the sounder (Mounting the Sounder, page2) and connect the power, marine network, transducer, and
sensors (Connecting the Sounder, page3).
GSD 26 Installation Instructions 5

Installing Locking Rings on the Cables
Before you install locking rings on the cables, you must route the cables.
To help make the cable-routing process easier, the locking rings are packaged separately from the cables. Each
locking ring is packaged in a small bag with a number on the label for easy identification.
1Separate the two halves of the locking ring .
2Align the two halves of the locking ring over the cable and snap them together.
3Insert the o-ring into the end of the connector.
Transducer Wiring Diagrams
NOTICE
Connecting the high-frequency wires to the low-frequency terminal block, or the low-frequency wires to the
high-frequency terminal block, damages the device and the transducer.
You can use these diagrams to identify the connection points for your transducer wires on the GSD 26 terminal
block. Locate your CHIRP/spread spectrum transducer model in the wiring color tables (Transducer Wire Color
Tables, page11) for more information.
The outer shield wire must connect to one of the two screw posts below the terminal block using the included
ring crimp terminal. When connecting two single-element transducers, you must connect the second transducer
to the duplicate set of connections on the right side of the terminal block.
TIP: The primary transducer cable wire housing covers the wiring bundles. To identify the wiring groups in the
bundles more easily, you can remove up to an inch of the cable housing.
6 GSD 26 Installation Instructions

Single-Element CHIRP/Spread Spectrum
GSD 26 Installation Instructions 7

Dual-Element CHIRP/Spread Spectrum with Temperature and XID
NOTE: The temperature and XID wires can be connected at either location.
8 GSD 26 Installation Instructions

Dual-Element CHIRP/Spread Spectrum with XID
NOTE: The XID wires can be connected at either location.
GSD 26 Installation Instructions 9

Dual-Element CHIRP/Spread Spectrum with Separate Temperature Sensor
NOTE: The temperature and XID wires can be connected at either location.
10 GSD 26 Installation Instructions