5.3.5. Check of serviceability of functioning of the sensor of temperature of cooling liquid (ECT)

The thermoswitch turns on the fan at a certain temperature of OZh. The switch should be checked if at a hot radiator the fan does not turn on. Before check of a thermoswitch be convinced of serviceability of its electrical wiring (see the Head Onboard electric equipment), and also the thermostat and the safety valve in a radiator cover. At any damage of the specified parts, the thermoswitch cannot work since at the same time it does not heat up cooling liquid.

The fan of a radiator can independently turn on at the switched-off engine and the included ignition (position "II" of the ignition key). Owing to the processes of the heat sink taking place in a motive compartment, it can repeatedly occur. Therefore, whenever possible, during the work in a motive compartment it is necessary to switch off ignition.


  1. Merge cooling liquid.
  2. Separate the thermoswitch socket. On petrol engines the thermoswitch is screwed in a radiator below about the right broad tank of the cooling system, and on the diesel engine - below at the left broad tank.
  3. Turn out a thermoswitch.
  4. Suspend a thermoswitch in a water bathtub and slowly heat water.

Check of the ECT sensor

  1. Check a thermoswitch chain by means of an ohmmeter. At the removed thermoswitch current should not pass (resistance is infinite). At the included condition of the switch current has to pass (resistance = 0 Ohms). At inclusion of a thermoswitch the click has to be heard distinctly.
  2. The thermoswitch has to join at a temperature approximately the 100th hail.
  3. Let's liquid be cooled in a water bathtub and check whether the thermoswitch works at a temperature of 95 a hail.
  4. If the thermoswitch does not correspond to the parameters stated above, it should be replaced.
  5. Screw a thermoswitch with a new sealing ring with effort of 20 Nanometers.
  6. Connect an electrical wiring.
  7. In conclusion of installation fill the cooling system and remove from it air.
  8. Warm up the engine and let's it work on single turns until the radiator fan turns on. Double-check the OZh level.