E 450 V8-5.4L (2009)
Compass: Description and Operation
Electronic Compass
Vehicles With Navigation
For vehicles with navigation, the compass signal originates from the Global Positioning System (GPS) signal. No calibration or zone adjustment is
available, as the compass heading is based on the GPS signal. The compass display is in the Front Display Interface Module (FDIM). Refer to Radio,
Stereo and Compact Disc for information on the GPS signal.
Vehicles Without Navigation
For vehicles without navigation, the compass signal originates from the compass module, which is integrated into the overhead console. A compass and
ambient air temperature display are contained in the overhead console. The ambient air temperature sensor is attached to the radiator frame located
behind the grille.
Compass Accuracy (Without Navigation)
Luggage racks and magnetic mounted devices like antennas should not be located on the front third of the vehicle roof. Placing these devices near the
compass causes inaccurate directional readings. If these devices must be used, accuracy of the compass may be improved by calibrating the compass
while the devices are installed on the vehicle.
Driving near power lines, or driving in the area of large iron or steel structures can temporarily change the compass heading. If the compass remains
inaccurate after driving near such objects, install a new compass sensor (part of the overhead console).
Most geographic areas (zones) have a magnetic north compass point that varies slightly from the northerly direction on maps. This variation is 4 degrees
between the adjacent zones and becomes noticeable as the vehicle crosses multiple zones. A correct zone setting eliminates the error. Refer to Compass
Zone Adjustment See: Adjustments/Compass Zone Adjustment.
Ambient Air Temperature
The ambient air temperature reading can be affected by engine heat when the vehicle is idling or has been off for less than 2 hours. The ambient air
temperature display limits the increase of the displayed air temperature to one degree per minute at very low speeds or immediately after the key is
turned to the ON position. After 2 minutes at a sustained speed of at least 53 km/h (33 mph), the effects of engine heat are minimal and the ambient air
temperature display shows the current ambient air temperature reading. Temperature decreases are always updated immediately.
If the ambient air temperature falls below 3.3°C (38°F), the ambient air temperature display alternates at a 2-second rate from "ICE" to the ambient air
temperature for one minute after starting the vehicle. After one minute has elapsed (after starting the vehicle), the ambient air temperature display shows
only the temperature reading.
