Gerry, are you trying to set a text readout of the heading? I don't have a Garmin, but on my Raymarine and Humminbird units, there are menu items for the display of data fields. Steve
On Edit:
I found this in the manual that was available on line... Not sure if it was what you were looking for...
Configuring Units of Measure
From the Home screen, select Configure > Preferences > Units.
System Units—global setting that defines individual units of measure at the same time. The options
are Statute (mh, ft., ºF), Metric (kh, m, ºC), Nautical (kt, ft., ºF), or Custom. Select Custom to
individually define units of measure for:
NOTE: You must be receiving NMEA Sonar depth data or using a Garmin sounder module to view
depth and temperature information.
Depth—individually set the units of measure for depth to Feet, Fathoms, or Meters.
Temperature—individually set the units of measure for temperature to Fahrenheit (ºF) or
Celsius (ºC).
Distance—individually set the units of measure for distance readings (Miles, Kilometers, or
Nautical Miles).
Speed—individually set the units of measure for speed readings (Miles Per Hour, Kilometers
Per Hour, or Knots).
Elevation—individually set the units of measure for elevation readings (Feet or Meters).
Volume—individually set the units of measure for volume readings (Liters, US Gallons, or
UK Gallons).
Pressure—individually set the units of measure for gauge (kPa or psi) and atmospheric
(Millibars or Inches of Mercury) pressure readings.
Heading—set the reference used in calculating heading information.
Auto Mag Var (Automatic Magnetic Variation)—automatically set the magnetic declination for
your location.
True—set true north as the heading reference.