GM Century/Lumina/Grand Prix/Intrigue 1997-2000

Temperature Gauge/Lamp Switch

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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.

TESTING



Temperature Gauge Inoperative or Inaccurate
  1. Disconnect the engine coolant temperature (gauge) sensor (usually a dark green wire).
  2.  
  3. Insert a 44 ohm resistor between the connector and ground.
  4.  
  5. Turn the ignition switch to the ON position. Does the gauge now read high, approximately 260°F (127°C)-
    1. If the gauge now reads high, check for a poor connection. If okay, replace the gauge sensor.
    2.  

  6.  
  7. 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.
  8.  

REMOVAL & INSTALLATION



  1. Record any radio anti-theft codes, as required. Disconnect the negative battery cable.
  2.  
  3. Locate the engine coolant temperature gauge sensor. It is usually below the coolant connection, just below the bleeder connection.
  4.  
  5. Partially drain the cooling system to a level below the sensor.
  6.  
  7. Unplug the electrical connector.
  8.  
  9. Unscrew the sensor from the engine.
  10.  



Click image to see an enlarged view

Fig. Coolant temperature gauge sensor-1997 3.4L (VIN X) engine shown

To install:

  1. Thread the sensor into the engine. Use care not to damage the "pigtail" wire.
  2.  
  3. Reconnect the lead wire.
  4.  
  5. Refill the cooling system with the proper mix of DEX-COOL® and water and properly bleed the cooling system. Please see .
  6.  
  7. Check for leaks.
  8.  

 
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