TEMPERATURE UPDATE - COLD
On power up, when the outside air temperature
sensed by the ambient temperature sensor is colder
than the stored memory temperature, the Compass/
Temp Mirror will update the displayed temperature
to the outside temperature at a rate of -1°F every 2
seconds, regardless if the vehicle is moving or not.
EXTREME TEMPERATURE / OPEN OR SHORT
CONDITION
If the measured outside temperature is more
than 60°C (140°F) or the ambient temperature
sensor sense circuit is shorted to ground, the temp
display will be 60°C (140°F) to indicate a short
circuit condition.
If the measured outside temperature is less than
-45°C (-49°F) or the ambient temperature sensor
sense circuit is open, the temp display will be -45°C
(-49°F) to indicate an open circuit condition.
AMBIENT TEMPERATURE SENSOR
DESCRIPTION
TheAmbient Temperature Sensor is hardwired to
the PCM. The ambient air temperature is moni-
tored and displayed by the Compass/Temp Mirror.
The ambient temperature sensor cannot be ad-
justed or repaired and, if faulty or damaged, it must
be replaced.
OPERATION
The resistance in the ambient temperature sen-
sor changes as the outside temperature rises or
falls. The PCM senses the change in reference
voltage through the ambient temperature sensor
resistor. Based on the resistance of the ambient
temperature sensor, the PCM is programmed to
correspond to a specific temperature. The Compass/
Temp Mirror then displays the proper ambient
temperature.
AMBIENT TEMPERATURE SENSOR
DIAGNOSTICS
The outside temperature function is supported by
the ambient temperature sensor, a signal and
ground circuit hardwired to the PCM and the
Compass/Temp Mirror display.
If the Compass/Temp Mirror display indicates
60°C (140°F) or the ambient temperature sensor
sense circuit is shorted to ground, the temp display
will be 60°C (140°F) to indicate a SHORT circuit
condition.
If the Compass/Temp Mirror display indicates
-45°C (-49°F) or the ambient temperature sensor
sense circuit is open, the temp display will be -45°C
(-49°F) to indicate an OPEN circuit condition.
If there is an OPEN or SHORT circuit condition,
it must be repaired before the Compass/Temp Mir-
ror VF display can be tested.
The ambient temperature sensor can be diag-
nosed using the following Sensor Test. If there are
no codes stored in the PCM and the ambient tem-
perature sensor and the circuits are confirmed to be
OK, but the temperature display is inoperative or
incorrect, replace the Compass/Temp Mirror.
AMBIENT TEMPERATURE SENSOR TEST
(1) Turn the ignition OFF.
(2) Disconnect and isolate the battery negative
cable.
(3) Disconnect the ambient temperature sensor
harness connector.
(4) Measure the resistance of the ambient tem-
perature sensor using the following values:
• 0° C (32° F) Sensor Resistance = 29.33 – 35.99
Kilohms
• 10° C (50° F) Sensor Resistance = 17.99 –
21.81 Kilohms
• 20° C (68° F) Sensor Resistance = 11.37 – 13.61
Kilohms
• 25° C (77° F) Sensor Resistance = 9.12 – 10.86
Kilohms
• 30° C (86° F) Sensor Resistance = 7.37 – 8.75
Kilohms
• 40° C (104° F) Sensor Resistance = 4.90 – 5.75
Kilohms
The sensor resistance should read between these
min/max values. If the resistance value is OK, refer
to the Wiring Diagrams to test the Signal and
Ground circuits. If the resistance values are not
OK, replace the Sensor.
3.4 EXTERIOR LIGHTING
The Headlamps are controlled by the Instrument
Cluster. The Instrument Cluster is also referred to
as a ‘‘Smart Cluster’’. It receives and sends mes-
sages to other modules through the PCI BUS cir-
cuit. The Headlamps are wired through the cluster
and then go to the Fuse Block to the lamps. Each
Headlamp has an independent fuse located in the
Fuse Block. For vehicles equipped with Daytime
Running Lamps, the DRL Module is integrated
with the Instrument Cluster.
3.5 ELECTRO/MECHANICAL INSTRUMENT
CLUSTER (EMIC)
There are 4 (four) different types of Instrument
Clusters. Base, Premium, Luxury, and AutoStick.
The Premium cluster is equipped with a tachometer
and a low fuel indicator. The Luxury has the same
features as the Premium with an additional black
overlay and chrome rings. The AutoStick is the
8
GENERAL INFORMATION
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