Temperature Gauge Is Inaccurate
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 1997 GMC Savana Special, 1997 GMC Savana Camper Special, 1997 GMC Savana, 1997 Chevrolet RV Cutaway, and 1997 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
- Warm engine to normal operating temperature. Compare engine temperature with coolant gauge reading. If readings are within 30 degrees of each other, gauge is operating properly. Check cooling system. If readings are not within 30 degrees of each other, go to next step.
- Disconnect coolant temperature sender harness connector. Using Tester (J-33431-B), connect Red tester lead to Dark Green wire terminal of temperature sender harness connector and other lead to ground. Adjust tester to 1305 ohms and check temperature gauge. Adjust tester to 49.5 ohms and observe temperature gauge. If temperature gauge indicates approximately 100 degrees and then approximately 260 degrees, replace coolant temperature sender. If temperature gauge does not indicate approximately 100 degrees and then approximately 260 degrees, go to next step.
- In previous step, if temperature gauge indicated significantly below hot at 49.5 ohms, go to next step. If temperature gauge did not indicate significantly below hot at 49.5 ohms, replace instrument cluster.
- Disconnect instrument cluster harness connector. Using ohmmeter, measure resistance between instrument panel harness connector terminal No. B9 (Dark Green wire) and temperature sender harness connector. If resistance is less than 20 ohms, replace instrument cluster. See INSTRUMENT CLUSTER under REMOVAL & INSTALLATION. If resistance is more than 20 ohms, repair Dark Green wire.