Log In
Search suggestions

    My Vehicles

    1973 Mazda 808 1.6L 2BL SOHC 4cyl

    My Store

    405 N COLLEGE ST
    (479) 443-4043

    OPEN 'til 10:00 PM today

    SAVE 20% ON ONLINE SHIP-TO-HOME ORDERS OF $100 OR MORE.

    Use Code: SEECLEAR

    See Details

    Mercury Villager 2000-2002

    Testing

    Print

    1. Let the engine cool completely before beginning the test.
    2.  
    3. Disconnect the sending unit wire.
    4.  
    5. Connect ohmmeter leads to the sending unit terminal and the negative battery terminal.
    6.  
    7. Start the engine and observe the ohmmeter. The resistance should gradually decrease as the engine warms up. When the engine has reached normal operating temperature, the resistance should be approximately 60-72 ohms. If not, replace the sending unit.

      Click image to see an enlarged view

      Fig. Checking the sending unit resistance. The resistance should decrease as the engine temperature increases

    8.  

    1. With the ignition switch OFF , disconnect the engine wiring harness from the ECT sensor.
    2.  
    3. Connect an ohmmeter between the ECT sensor terminals.
    4.  
    5. With the engine cold and the ignition switch in the OFF position, measure and note the ECT sensor resistance.
    6.  
    7. Connect the engine wiring harness to the sensor.
    8.  
    9. Start the engine and allow the engine to reach normal operating temperature.
    10.  
    11. Once the engine has reached normal operating temperature, turn the engine OFF .
    12.  
    13. Once again, disconnect the engine wiring harness from the ECT sensor.
    14.  
    15. Measure and note the ECT sensor resistance with the engine hot.
    16.  
    17. Compare the cold and hot ECT sensor resistance measurements with those in the chart. If the resistances are not within specifications, replace the sensor.

      Click image to see an enlarged view

      Fig. Disconnect the ECT sensor electrical connector to test the sensor



      Click image to see an enlarged view

      Fig. Another method of testing the ECT sensor is to submerge it in cold or hot water and check resistance



      Click image to see an enlarged view

      Fig. ECT sensor resistance-to-temperature specifications

    18.  

     
    AutoZone Logo