Fan, Cooling: Description

The radiator and air conditioner condenser cooling system consists of two electric fans operated at two different speeds, by means of a series/parallel connection:

• the first speed is activated at a first engine coolant temperature level and a certain air conditioning refrigerant fluid pressure;
• the second speed comes on at a higher temperature or pressure levels.

The fans are operated by three specific relay switches, two located in the engine compartment control unit and one located directly on the radiator.

The supply line for the fans is protected by two special fuses, located in the engine compartment junction unit.

FUNCTIONAL DESCRIPTION 

Relay switches T06 and T07 of the engine compartment junction unit B001 and engine cooling fan relay switch J028 - located on the radiator - manage the operation of the two fans N011 and N012 in serial/parallel mode; the relay switch power lines are protected by fuses F06 and F07, in engine compartment junction unit B001.

The supply line for the engine cooling fan relay switch J028 is protected by fuse F18, also located in the engine compartment junction unit B001.

If the engine coolant reaches an initial temperature level or linear sensor K120 indicates to the engine management control unit M010 - pin 47 of connector A - that a certain pressure level has been reached, a signal is sent - from pin 38 of connector A - that triggers the low speed relay switch T06, which then sends power to fans N011 and N012 which are connected in series and turn the fan at the first speed (slow).

The linear sensor K120 receives a power supply and reference ground from the engine management control unit M010, pins 10 and 15 of connector A.

If the engine coolant reaches a higher temperature level or the linear sensor K120 indicates to the engine management control unit M010 that a certain pressure level has been reached, a signal is sent - from pin 36 of connector A - that triggers the high speed relay switch, T07 and the engine cooling fan relay switch J028. Fans N011 and N012 which are connected in parallel and thus turn the fan at the top speed, are then supplied. The engine temperature sensor K036 measures the engine temperature and receives a reference ground from pin 55 of connector B of the engine management control unit M010 and sends a signal proportional to the engine fluid temperature to pin 63 of connector B.

The engine cooling auxiliary electric pump N212 is managed by the engine management control unit M010 which activates relay switch T17 from pin 23 of connector A through a negative signal, thus supplying the auxiliary pump motor. The power supply line is protected by fuse F84 which is located in the engine compartment junction unit.