How to Test a Chevrolet Coolant Temperature Sensor

by Russell Wood
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The coolant temperature sensor on a Chevrolet engine is used by the vehicle's computer to determine how hot or cold the coolant flowing through the engine block is at any given time, so that the computer knows how to properly run the engine. It's difficult to know if the sensor is broken just from normal operation of the vehicle; to find out, you have to test the sensor itself. In this case, the project vehicle is a 2005 Chevrolet Silverado, but the process is similar for other Chevrolet vehicles as well.

Step 1

Allow the vehicle to cool completely. Lift up the front end using the jack, and set the frame down onto a pair of jack stands.

Step 2

Locate the coolant temperature sensor on the driver's side of the engine block, just behind the power steering pump. Unplug the electrical connection to the switch with your hands, revealing two posts on the sensor. Set the multimeter to the Ohm symbol for resistance. Hold the black lead from the multimeter on one post of the switch and the red lead on the other. Note the number on the multimeter, then remove the connections from the sensor.

Step 3

Turn on the engine and allow it to run for 5 minutes, or until the temperature starts to go up. Test the sensor again with the multimeter. If the number on the multimeter is lower than the reading you got in Step 2, the sensor is working correctly. If not, it needs to be replaced.

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