Chrysler RAM TRUCK 2500 1994 Service Manual page 354

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OVERHEAD CONSOLE 8C - 7
COMPASS REPAIR PROCEDURES
VARIATION ADJUSTMENT PROCEDURE
Variance is the difference between magnetic north
and geographic north. I n some areas the difference
between magnetic and geographic north is great
enough to cause the compass to give false readings. I f
this occurs, the variance must be set.
To set the variance: turn key to the ON position.
Depress both buttons and hold down until VAR light
appears. This takes about 5 seconds.
Release both buttons.
Using the map (Fig. 1) find your geographic loca­
tion and note the zone number.
Press the US/METRIC button to sequentially go
through the numbers until the zone number for your
area appears i n the display.
Press the COMP/TEMP button to enter this zone
number.
Confirm correct directions are indicated.
Fig. 1 Variance Settings
COMPASS CALIBRATION PROCEDURE
CAUTION: DO NOT u s e magnetic tools when servic­
ing the overhead console.
CAUTION: DO NOT place any external magnets
s u c h a s magnetic roof mount antennas, in the vicin­
ity of the compass.
Do not attempt to set compass near large metal ob­
jects such as other vehicles, large buildings or
bridges. The compass features an "Auto-Cal" design
which simplifies the calibration procedure. During
normal driving this feature automatically updates
the compass calibration. This takes into account
small changes i n magnetism the vehicle may see over
its lifetime.
Calibrate the compass manually as follows:
(1) Start the engine.
(2) Depress both buttons and hold down until CAL
display appears. This takes about 10 seconds and ap­
pears about 5 seconds after the VAR display appears.
(3) Release buttons.
(4) Drive vehicle on a level surface that is away
from metal objects through 3 or more complete cir­
cles, i n not less than 48 seconds. The CAL display
will go off and the compass is now calibrated.
If C A L display does not go off, either there is
excessive magnetism near the compass or the
unit is defective. Repeat the demagnetizing and
calibration procedures at least one more time.
If the wrong direction is still indicated, the
area selected may be too close to a magnetic
source. Repeat the calibration procedure i n an­
other location.
DEMAGNETIZING PROCEDURE
The tool used to demagnetize the forward console
attaching screw and roof panel is the Miller Tool
6029. Equivalent units must be rated as continuous
duty for 110/115 volts and 60Hz. They must also
have a field strength of over 350 gauss at 1/4-inch
beyond the tip of the probe.
I n this procedure the demagnetizing tool is used to
demagnetize both the roof panel and console forward
mounting screw.
(1) Be sure the ignition switch is i n the OFF posi­
tion before you begin the demagnetizing procedures.
(2) Plug the demagnetizing tool into a 110/115 volt
outlet while keeping the tool at least 2 inches away
from the compass area.
CONSOLE F0RWAR0 MOUNTING SCREW
(3) Slowly approach the head of the forward
mounting screw with the plastic coated tip of the de­
magnetizing tool. Contact the head of the screw for
about 2 seconds.
(4) With the demagnetizing tool still energized,
slowly back i t away from the screw until the tool is
at least 2 inches from the screw head. Unplug the
tool.