Dodge 2000 DURANGO Service Manual page 500

8V - 6 OVERHEAD CONSOLE SYSTEMS
DIAGNOSIS AND TESTING (Continued)
AMBIENT TEMPERATURE SENSOR
The thermometer function is supported by the
ambient temperature sensor, a wiring circuit, and a
portion of the compass mini-trip computer module. If
any portion of the ambient temperature sensor cir-
cuit fails, the compass/thermometer display function
will self-diagnose the circuit. An "SC" (short circuit)
will appear in the display in place of the tempera-
ture, when the sensor is exposed to temperatures
above 110° C (230° F), or if the sensor circuit is
shorted. An "OC" (open circuit) will appear in the dis-
play in place of the temperature, when the sensor is
exposed to temperatures below –50° C (–58° F), or if
the sensor circuit is open.
The ambient temperature sensor circuit can also be
diagnosed using the following Sensor Test, and Sen-
sor Circuit Test. If the temperature sensor and cir-
cuit are confirmed to be OK, but the temperature
display is inoperative or incorrect, refer to Compass
Mini-Trip Computer in the Diagnosis and Testing
section of this group. For complete circuit diagrams,
refer to Overhead Console in the Contents of
Group 8W - Wiring Diagrams.
SENSOR TEST
(1) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Disconnect the ambient temperature sensor wire har-
ness connector.
(2) Measure the resistance of the ambient temper-
ature sensor. At –40° C (–40° F), the sensor resis-
tance is 336 kilohms. At 55° C (131° F), the sensor
resistance is 2.488 kilohms. The sensor resistance
should read between these two values. If OK, refer to
Sensor Circuit Test in the Diagnosis and Testing
section of this group. If not OK, replace the faulty
ambient temperature sensor.
SENSOR CIRCUIT TEST
(1) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Disconnect the ambient temperature sensor wire har-
ness connector and the overhead console wire har-
ness connector.
(2) Connect a jumper wire between the two termi-
nals in the body half of the ambient temperature sen-
sor wire harness connector.
(3) Check for continuity between the sensor return
circuit and the ambient temperature sensor signal
circuit cavities of the roof wire harness overhead con-
sole connector. There should be continuity. If OK, go
to Step 4. If not OK, repair the open sensor return
circuit or ambient temperature sensor signal circuit
to the ambient temperature sensor as required.
(4) Remove the jumper wire from the body half of
the ambient temperature sensor wire harness con-
nector. Check for continuity between the sensor
return circuit cavity of the roof wire harness over-
head console connector and a good ground. There
should be no continuity. If OK, go to Step 5. If not
OK, repair the shorted sensor return circuit as
required.
(5) Check for continuity between the ambient tem-
perature sensor signal circuit cavity of the roof wire
harness overhead console connector and a good
ground. There should be no continuity. If OK, refer to
Compass Mini-Trip Computer in the Diagnosis
and Testing section of this group. If not OK, repair
the shorted ambient temperature sensor signal cir-
cuit as required.
SERVICE PROCEDURES
COMPASS VARIATION ADJUSTMENT
Compass variance, also known as magnetic decli-
nation, is the difference in angle between magnetic
north and true geographic north. In some geographic
locations, the difference between magnetic and geo-
graphic north is great enough to cause the compass
to give false readings. If this problem occurs, the
compass variance must be set.
To set the compass variance:
(1) Using the Variance Settings map, find your
geographic location and note the zone number (Fig.
2).
(2) Turn the ignition switch to the On position. If
the compass/temperature data is not currently being
displayed, momentarily depress and release the Step
push button to step through the display options until
you have reached the compass/temperature display.
(3) Depress both the U.S./Metric, and the Step
push buttons and hold the buttons down until "VAR"
appears in the display. This takes about five seconds.
(4) Release both of the push buttons. "VAR" along
with the current variance zone will appear in the dis-
play.
(5) Momentarily depress and release the U.S./Met-
ric push button to step through the zone numbers,
until the zone number for your geographic location
appears in the display.
(6) Momentarily depress and release the Step push
button to enter the displayed zone number into the
compass unit memory.
(7) Confirm that the correct directions are now
indicated by the compass.
COMPASS CALIBRATION
CAUTION: Do not place any external magnets, such
as magnetic roof mount antennas, in the vicinity of
the compass. Do not use magnetic tools when ser-
vicing the overhead console.
DN