Overhead temp.
Could it be a failure/malfunction of the ambient temperature sensor that is located under the hood? I would be inclined to swap a buddies in to check if it needs to be replaced.
Manual for the 03 says:
DIAGNOSIS AND TESTING - AMBIENT TEMPERATURE SENSOR
(1) Turn the ignition switch to the Off position. Disconnect and isolate the battery negative cable. Disconnect the ambient temperature sensor wire harness connector.
(2) Measure the resistance of the ambient temperature sensor. At 24° C (75° F), the sensor resistance should be approximately 10.3 kilohms. At 30° C (86°
F), the sensor resistance should be approximately 7.57 kilohms. The sensor resistance should decrease as the temperature rises. If OK, refer to Diagnosis
and Testing - Ambient Temperature Sensor Circuit. If not OK, replace the faulty ambient temperature sensor.
NOTE: The ambient temperature sensor is a very sensitive device. When testing, be certain the temperature sensor has had time to stabilize (room
temperature) before attempting to read the sensor resistance. Failure to let the ambient temperature sensor temperature stabilize could result in a misleading test.
DIAGNOSIS AND TESTING - AMBIENT TEMPERATURE SENSOR CIRCUIT
(1) Turn the ignition switch to the Off position. Disconnect and isolate the battery negative cable. Disconnect the ambient temperature sensor wire harness connector and the Front Control Module wire harness connector.
(2) Connect a jumper wire between the two terminals of the ambient temperature sensor wire harness connector.
(3) Check for continuity between the sensor return circuit and the ambient temperature sensor signal circuit cavities of the Front Control Module wire harness connector. There should be continuity. If OK, go to Step 4. If not OK, repair the open sensor return or signal circuit as required.
(4) Remove the jumper wire from the ambient temperature
sensor wire harness connector. Check for continuity between the sensor return circuit cavity of the Front Control Module wire harness 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 temperature
sensor signal circuit cavity of the Front Control Module wire harness connector and a good ground. There should be no continuity. If OK, Diagnosis and Test - Overhead Console. If not OK, repair the shorted ambient temperature sensor signal circuit as required.
Manual for the 03 says:
DIAGNOSIS AND TESTING - AMBIENT TEMPERATURE SENSOR
(1) Turn the ignition switch to the Off position. Disconnect and isolate the battery negative cable. Disconnect the ambient temperature sensor wire harness connector.
(2) Measure the resistance of the ambient temperature sensor. At 24° C (75° F), the sensor resistance should be approximately 10.3 kilohms. At 30° C (86°
F), the sensor resistance should be approximately 7.57 kilohms. The sensor resistance should decrease as the temperature rises. If OK, refer to Diagnosis
and Testing - Ambient Temperature Sensor Circuit. If not OK, replace the faulty ambient temperature sensor.
NOTE: The ambient temperature sensor is a very sensitive device. When testing, be certain the temperature sensor has had time to stabilize (room
temperature) before attempting to read the sensor resistance. Failure to let the ambient temperature sensor temperature stabilize could result in a misleading test.
DIAGNOSIS AND TESTING - AMBIENT TEMPERATURE SENSOR CIRCUIT
(1) Turn the ignition switch to the Off position. Disconnect and isolate the battery negative cable. Disconnect the ambient temperature sensor wire harness connector and the Front Control Module wire harness connector.
(2) Connect a jumper wire between the two terminals of the ambient temperature sensor wire harness connector.
(3) Check for continuity between the sensor return circuit and the ambient temperature sensor signal circuit cavities of the Front Control Module wire harness connector. There should be continuity. If OK, go to Step 4. If not OK, repair the open sensor return or signal circuit as required.
(4) Remove the jumper wire from the ambient temperature
sensor wire harness connector. Check for continuity between the sensor return circuit cavity of the Front Control Module wire harness 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 temperature
sensor signal circuit cavity of the Front Control Module wire harness connector and a good ground. There should be no continuity. If OK, Diagnosis and Test - Overhead Console. If not OK, repair the shorted ambient temperature sensor signal circuit as required.
Thread
Thread Starter
Forum
Replies
Last Post
H8GAS
3rd Gen High Performance and Accessories (5.9L Only)
18
Aug 3, 2007 06:31 PM
jrs_dodge_diesel
2nd Gen. Dodge Ram - No Drivetrain
10
Jan 19, 2004 10:18 PM



