Testing Water Temperature Sensor

Put the gas control knob to the off position wait a few minutes and then try to light the pilot as normal.

Testing water temperature sensor.

Gently lower the end of the sensor into the water until the entire device is fully submerged. How to control a coolant temperature sensor without removal. Connect the black lead of the digital ohm meter to a solid grounding. Testing the coolant temperature sensor is a very quick process.

Most pro s test actual voltage coming out of the engine coolant temperature sensor. Note the number on the multimeter then remove the connections from the sensor. Our water quality testing equipment is designed for use in the field. Many inexpensive shop manuals tell you to test an engine coolant temperature sensor using an ohmmeter.

Wait a minute or so for the screen to give you a reading of the cold water. This can be any solid piece of metal. Test the sensor again with the multimeter. If the unit doesn t come on and still codes then you need to take the gas valve apart.

If you were to test the coolant temperature sensor alone you may think that it failed because its resistance value has remained at about 1500 or 2100 ohms for example when in fact the sensor is reporting the coolant actual temperature and it s working properly. This video does not constitute or replace a real specialized technical man. You could relay on the temperature gauge on your dashboard. See the diagram below for where to test voltage.

Most newer water heaters use honeywell gas valves. Turn on the engine and allow it to run for 5 minutes or until the temperature starts to go up. Submerge the sensor in the water and take a reading. Once you have a reading write down the measurement for reference.

You can do that but it s not a very accurate test. The water temperature sensor is capable of measuring temperature in the range of 5 degrees centigrade to 50 degrees centigrade or 23 degrees fahrenheit to 122 degrees fahrenheit with a resolution of 0 1 degree.