Checking the overheat protection thermostat

Fig 1: Identifying Ignition OFF

Courtesy of VOLVO CARS OF NORTH AMERICA.

• Ignition off.

  Measure between the overheat protection thermostat terminals using an ohmmeter. The resistance must be approximately 0 Ω.

  The overheat protection thermostat must be replaced if the value is not correct.

  Other information: 

  • To access or replace the overheat protection thermostat:
    • For cars manufactured up to w38 2001 inclusive, see Overheat protection thermostat / flame sensor / engine coolant temperature sensor, replacing
    • For cars manufactured from w39 2001 inclusive, see Replacing the overheat protection thermostat, the flame sensor and the engine coolant temperature sensor .
  Fig 2: Identifying Overheat Protection Thermostat

  Courtesy of VOLVO CARS OF NORTH AMERICA.
  Fig 3: Identifying Ohm Meter

  Courtesy of VOLVO CARS OF NORTH AMERICA.

Was a fault detected? 

• YES 

  Refer to Verification 

• NO 

  Refer to Checking components and wiring