Garmin GPS III Plus User Manual

The Garmin GPS III Plus is a rugged, handheld GPS receiver featuring a high-contrast LCD display, 12 parallel channel reception, built-in worldwide basemap, WAAS-enabled for improved accuracy, and multiple navigation modes. It supports waypoint, route, and track log management, includes a trip computer, and offers customizable data fields. Below are key sections for safety, features, installation, setup, operation, and troubleshooting.

1. Features at a Glance 2. Installation & Power 3. First-Time Setup 4. Specifications 5. Controls and Display 6. Basic Navigation 7. Advanced Features 8. Data Management 9. Care & Maintenance 10. Regulatory Information 11. Troubleshooting

Features at a Glance

Key components: High-contrast LCD screen, Rocker keypad, ENTER key, PAGE key, POWER key, external antenna port, and data/power connector.

Feature	Description
12-Channel Receiver	Parallel tracking for fast satellite acquisition
Built-in Worldwide Basemap	Includes cities, highways, and major landmarks
WAAS Enabled	Provides enhanced position accuracy
Navigation Modes	Supports GPS, DGPS, and Simulator modes
Waypoint & Route Storage	Stores up to 500 waypoints and 20 reversible routes
Trip Computer	Displays speed, heading, distance, and time data
External Antenna Port	For connection to an optional external antenna
Data/Power Connector	For PC interface and external power (optional cable)
Waterproof Case	Meets IEC 529 IPX7 standards
Backlit Display	For use in low-light conditions

Installation & Power

Unpack and inspect contents. Install batteries or connect to external power.

Install Batteries: Open battery compartment on back, insert 4 AA batteries (alkaline or NiMH).
External Power: Use optional power/data cable to connect to a 12V DC source.
External Antenna: Connect optional external antenna to the MCX connector for improved reception.
Initial Power On: Press and hold POWER key for 2 seconds.

WARNING! Use only recommended batteries. Do not short-circuit battery terminals.

First-Time Setup

Power on the unit; follow on-screen prompts.

Acquire Satellites: Go outdoors with a clear view of the sky. The unit will automatically search for satellites.
Set Initial Position: If prompted, use the rocker key to enter your approximate location or select "Automatic".
Configure Units: In the SETUP menu, select units of measure (statute, nautical, metric).
Set Time Format: Choose 12-hour or 24-hour format and set local time offset.
Calibrate Compass (if applicable): Follow on-screen instructions.

CAUTION! For first-time satellite acquisition, allow up to 15 minutes outdoors.

Specifications

Receiver: 12 parallel channels, WAAS enabled.
Update Rate: 1 second continuous.
Accuracy: <15 meters RMS (GPS), <3 meters RMS (WAAS).
Display: 4.2 x 2.2 inch, 160 x 288 pixel LCD with backlight.
Interface: RS-232 serial (NMEA 0183, GARMIN proprietary).
Power: 4 AA batteries (approx. 20 hours) or 10-40V DC external.
Waterproof: IEC 529 IPX7 (submersible to 1 meter for 30 minutes).
Operating Temp: -15°C to 70°C (5°F to 158°F).
Storage Temp: -40°C to 85°C (-40°F to 185°F).
Weight: 9.9 oz (280 g) with batteries.

Controls and Display

Access functions via front panel keys. PAGE key cycles through main screens (Satellite, Map, Navigation, Highway, Trip Computer).

Key Functions: POWER (On/Off/Backlight), ROCKER (Move cursor/Select), ENTER (Confirm/Select), PAGE (Cycle screens), QUIT (Cancel/Go back).

Display Pages: Satellite Page (shows satellite signal strength and position), Map Page (displays your position on the basemap), Navigation Page (shows bearing, distance, and steering guidance), Highway Page (simplified compass display), Trip Computer Page (shows speed, odometer, trip time, etc.).

Basic Navigation

Navigate to a waypoint, follow a route, or track your path.

Create a Waypoint: Press and hold ENTER at your current location or use the rocker to mark a position on the map.
Go To a Waypoint: From the Main Menu, select "Go To", then choose a waypoint from the list.
Follow a Route: From the Main Menu, select "Routes", choose a route, and select "Navigate".
Use the Map: Your current position is shown as a triangle. The track log shows your path.
Stop Navigation: From the Navigation Page, press QUIT and select "Stop Navigation".

Tip: For best accuracy, ensure you have a clear view of the sky.

Advanced Features

Simulator Mode: Practice navigation indoors. Access via SETUP > System > Mode > Simulator.

TracBack® Feature: Retrace your path back to the starting point. Access from the Track Log menu.

Proximity Waypoints: Set alarms for approaching specific points or boundaries.

Sun & Moon Information: View sunrise, sunset, moonrise, and moonset times for your location.

Area Calculation: Calculate the area of a plotted polygon on the map.

Data Management

Connect to a PC: Use the optional PC interface cable to transfer waypoints, routes, and tracks.

Clear Memory: From the Main Menu, go to Setup > System > Clear Memory. Use with caution.

Backup Data: Regularly upload data to your PC to prevent loss.

Care & Maintenance

Clean the case with a damp cloth. Do not use harsh chemicals or abrasives.

Battery Care: Remove batteries if the unit will not be used for an extended period. Use only compatible battery types.

CAUTION! Do not open the case. There are no user-serviceable parts inside.

Regulatory Information

FCC Compliance: This device complies with Part 15 of the FCC Rules. Operation is subject to the condition that this device does not cause harmful interference. Copyright © Garmin Ltd. or its subsidiaries. Garmin and the Garmin logo are trademarks of Garmin Ltd. or its subsidiaries. For support, visit www.garmin.com/support or contact Garmin Product Support.

Troubleshooting

Symptom	Possible Cause	Corrective Action
Unit will not power on	Dead batteries, improper installation	Install fresh batteries; ensure correct polarity.
Poor satellite reception	Obstructed view, weak batteries	Move to an open area; replace batteries; connect external antenna.
Inaccurate position	WAAS not enabled, multipath interference	Enable WAAS in Setup; move away from tall buildings/reflective surfaces.
Display is blank/dim	Backlight off, contrast setting	Press POWER to adjust backlight; adjust contrast in Setup.
Buttons not responding	Unit locked, low battery	Press and hold QUIT to unlock; replace batteries.
PC interface not working	Wrong cable, incorrect settings	Use Garmin cable; ensure correct COM port and baud rate (9600) are selected in PC software.

Reset: Press and hold POWER + PAGE + ENTER while powering on to perform a master reset (erases all user data).

Service: Contact Garmin Product Support or visit an authorized service center.