Chrysler Full-Size Trucks 1989-1996 Repair Guide

Coolant Temperature Sensor

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OPERATION



See Figures 1, 2 and 3

The engine coolant temperature sensor, located in the intake manifold near the thermostat housing, informs the computer when the coolant temperature reaches a predetermined operating level. Its signals to the computer also help to control the amount of spark advance with a cold engine.



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Fig. Fig. 1: Location of the engine coolant temperature sensor-4-cylinder engine



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Fig. Fig. 2: Location of the engine coolant temperature sensor-V6 and V8 engines



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Fig. Fig. 3: Location of the engine coolant temperature sensor-V10 engine

TESTING



  1. Disengage the wire harness connector from the sensor.
  2.  
  3. Connect the leads of an ohmmeter to the terminals of the sensor.
  4.  
  5. With the engine cold and the ambient temperature less than 90°F (32°), the resistance should be between 500-1100 ohms.
  6.  
  7. With the engine at normal operating temperature, the resistance should be greater than 1300 ohms.
  8.  

The sensor will continually change its resistance with a change in engine operating temperature.

  1. If the resistance is not within the specified ranges, replace the sensor.
  2.  

REMOVAL & INSTALLATION




CAUTION
If the engine was previously in operation, do not attempt to drain the cooling system until the engine has had sufficient time to cool. Coolant reaches extremely high temperatures and can gush out of a hot system and scald you, causing severe injury.

The engine coolant temperature sensor is behind and below the engine thermostat on 2.5L engines, the intake manifold on V6 and V8 engines, and in the thermostat housing on the V10 engine.

  1. Partially drain the cooling system to below the level of the coolant temperature sensor.
  2.  
  3. On V6 and V8 engine: Remove the air cleaner housing assembly.
  4.  

On V6 and V8 engines with air conditioning, you may need to fabricate an 8 in. (20 cm) L-shaped hook tool from a coat hanger to pull the electrical connector. This connector is snapped into place, but not lock tab equipped.

  1. Unplug the electrical connector, then unthread and remove the sensor.
  2.  

 
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