1. Turn the ignition switch to the RUN position.
2. Disconnect the engine coolant temperature (ECT) sensor.
3. Connect the red lead of a J 33431-C to the ECT sensor connector.
4. Connect the other lead of the tester to ground.
5. Set the resistance dial to 1400 ohms.
6. Slowly move the resistance dial to 50 ohms.

Did the temperature gauge read COLD at first and then slowly move to the full HOT position?

50 ohms-1400 ohms

Go to Step 2

Go to Step 3

Replace the ECT sensor. Refer to Engine Coolant Temperature Sensor Replacement , Engine Coolant Temperature Sensor Replacement 5.7L, Engine Coolant Temperature Sensor Replacement 6.5L (L57), Engine Coolant Temperature Sensor Replacement 6.5L (L65), or Engine Coolant Temperature Sensor Replacement 7.4L in Engine Controls.

Is the repair complete?

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System OK

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1. Turn the ignition to the OFF position.
2. Disconnect the instrument cluster.
3. Use aJ 39200 DMM to measure the resistance between the instrument cluster connector, cavity 13 and the ECT sensor connector, cavity A.

Is the resistance greater than the specified value?

5.0 ohms

Go to Step 4

Go to Step 5

Repair the high resistance in CKT 35 (DK GRN) between the instrument cluster connector and the ECT sensor connector.

Is the repair complete?

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System OK

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Replace the instrument cluster.

Is the repair complete?

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System OK

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