Land Rover Discovery Owners & Service Manuals

Land Rover Discovery: Electric Cooling Fan

Electric Cooling Fan

  1. Fan shroud
  2. Cooling fan motor
  3. Electrical connection
  4. Speed flaps

An electric, variable speed cooling fan is installed in a shroud attached to the rear of the radiator. The cooling fan is operated by an electric cooling fan control module, integrated into the electric motor, under the control of the ECM via a PWM signal. An electrical connector at the right side of the shroud provides the interface between the cooling fan harness and the vehicle wiring.

The electric cooling fan control module is provided with:

  • A battery power supply from the engine junction box (EJB)..
  • An ignition signal from the ECM relay in the EJB.
  • A PWM signal from the ECM.
  • A ground.

The ECM varies the PWM signal to the fan control module between 0 and 100% to operate the fan motor in one of four modes:

  • Off
  • Minimum speed (750 rev/min).
  • Linear variable speed between minimum and maximum speeds.
  • Maximum speed (2820 rev/min).

Under hot operating conditions, the electric cooling fan may continue to operate for up to five minutes after the engine has been switched off.

The system is protected against abnormal internal temperature by measuring its internal temperature at two points with temperature sensors.

  • Sensor 1 : This sensor is used to calculate the temperature of active components near the micro controller. The fan will stop immediately if the fan internal temperature reaches 135ºC (275ºF). At motor stop, after a delay of 120 seconds the diagnostic feedback will be sent. Normal operation will resume once the temperature is less than 120ºC (248ºF).
  • Sensor 2 : This sensor is used to measure the temperature of the power stage of the PCBA (near the metal oxide semi-conductor field effect transistors (MOSFETs)) to reduce the power if the temperature is too high (derating) and to stop the motor in case of an over temperature condition

The fan will derate if the powerstage internal temperature reaches 135ºC (275ºF) and stop motor function at 145ºC (293ºF). At motor stop, after a delay of 120 seconds the diagnostic feedback will be sent. Normal fan operation will resume once the powerstage temperature falls to 135ºC (275ºF).



  1. Pipe connection - coolant expansion line from radiator
  2. Pipe connection - coolant expansion line from engine thermostat housing
  3. O-ring seal
  4. Cap
  5. Bolt and washer
  6. Coolant expansion tank
  7. Location grommet
  8. Coolant level sensor
  9. Hose connection to coolant pump

The coolant expansion tank is located in the left side of the engine compartment. The tank is located by a grommet on its underside and positively secured with a bolt and washer to a bracket on the vehicle body and a second bracket that locates in a molded slot in the tank body.

The coolant expansion tank has three connections; one for radiator bleed, one for engine bleed and one for outlet to the thermostat housing.

An engine coolant level sensor is located in the underside of the tank body.

The sensor reacts to the influence of a magnetic field. A float, with integral magnet, is located inside the tank, over the sensor tube. The sensor has contacts inside the tube, which are normally open. When the fluid level reduces, the magnetic float moves down the tube. When the magnet reaches the sensor contacts, the magnetic field closes the contacts. The sensor connects hardwired to the Central Junction Box (CJB) which receives the signals from the sensor. Maximum and minimum marks are molded on the tank body.

The coolant expansion tank provides the following functions:

  • Service fill.
  • Coolant expansion during warm-up
  • Air separation during operation.
  • System pressurization by the filler cap.


     Electric Thermostat

    Thermostat housing Heater element Temperature sensor The electric thermostat independently controls the engine coolant flow to the cylinder head and cylinder block, improving engine warm-up tim

     Engine Cooling - Ingenium i4 2.0l Diesel / Diagnosis and Testing

    PRINCIPLES OF OPERATION For a detailed description of the Engine Cooling system, refer to the relevant Description and Operation section in the workshop manual. REFER to: Engine Cooling (303-03B Engi

     Engine Emission Control - Ingenium i4 2.0l Diesel Diesel Exhaust Fluid Filler Assembly (G1875908) / Removal and Installation

    REMOVAL WARNING: Make sure to support the vehicle with axle stands. Raise and support the vehicle. Refer to: Diesel Exhaust Fluid Tank Drain and Refill (303-08B Engine Emission Control - INGENIUM I4 2


     Wheels and Tires - Description

    TIRE LOCATION Because of the requirement for different pressure targets and thresholds for the front and rear tires, the Tire Pressure Monitoring System (TPMS) can identify the location of the tires on the vehicle, and assign received tire pressure sensor identification to a specific position on the

     General warning/ information message (amber)

    Illuminates when a non-critical warning message or an information message is available in the Message centre. GLOW PLUGS (AMBER) Illuminates when the ignition is switched on, to indicate that the glow plugs are active. LOW FUEL WARNING (AMBER) Illuminates when the fuel level is low. Refuel at the ea

    © 2019-2024 Copyright