The temperature gauge/lamp switch activates a warning lamp in the instrument cluster if the engine overheats. With optional instrumentation, a temperature gauge replaces the warning lamp and the temperature switch is replaced with a transducer. These sensors are self-grounded to the engine. During installation, no sealer tape should be used since it can interfere with the sensor's ground path. As a general specification, this resistance-based sensor should show about 1365 ohms at 100°F (38°C) and 44 ohms at 280°F (138°C). A special tester is recommended by the factory. Resistors of equal value may be used.
Removal & Installation
- Record any radio anti-theft codes, as required. Disconnect the negative battery cable.
- Locate the engine coolant temperature gauge sensor. It is usually below the coolant connection, just below the bleeder connection.
- Partially drain the cooling system to a level below the sensor.
- Unplug the electrical connector.
- Unscrew the sensor from the engine.
- Thread the sensor into the engine. Use care not to damage the "pigtail" wire.
- Reconnect the lead wire.
- Refill the cooling system with the proper mix of DEX-COOL® and water and properly bleed the cooling system.
- Check for leaks.
Temperature Gauge Inoperative Or Inaccurate
- Disconnect the engine coolant temperature (gauge) sensor (usually a dark green wire).
- Insert a 44 ohm resistor between the connector and ground.
- Turn the ignition switch to the ON position. Does the gauge now read high, approximately 260°F (127°C)-
- If the gauge now reads high, check for a poor connection. If okay, replace the gauge sensor.
- If the gauge shows no change, check for a bad connection at the instrument cluster, or a short to voltage between the instrument cluster connector and the gauge sensor. If these circuits are okay, it may be necessary to service the instrument cluster.