Introduction
The radiator fans are powered via a specific relay, which is enabled by the engine control unit.
Component assembling position

A injection relay; b etv relay (throttle valve actuator motor), c radiator fan relay, d engine control unit.

Location of right hand fan connection.

Location of left hand fan connection.
Connection wiring diagram

Ccm engine control connection, t radiator fan relay, a key on power (+15 from hands free relay 30), r battery power (+30), l left hand fan, r right hand fan, 85 light blue/black - lb/bk, 30 red/green - r/g, 86 red/black - r/bk, 87 red/grey - r/gr.
In the event of fault
In the event of a radiator fan relay fault, the radiator fans themselves do not work. The relay is not commanded by the ecu.
Fault codes generated and possible correlated faults fault codes generated by the engine control unit and displayed by the dds (fan relay diagnosis):
Note
Check integrity of electric circuit - short-circuit to vdc = with dashboard on, using a voltmeter, a voltage is measured between the wire tested and ground.
Check integrity of electric circuit - short-circuit to ground = with the battery cables disconnected, using an ohmmeter, continuity is detected between the wire tested and ground.
Check integrity of electric circuit - open circuit = with the battery cables disconnected, using an ohmmeter, no continuity is detected between the two ends of the wire tested.
The dashboard service display shows the error "fan relay" and the eobd warning light activates.
Possible correlated faults: coolant reaches boiling point but radiator fans not working. Check:
The radiator fan relay may be actuated from the dds to check radiator fan function.
The fans are normally activated at 103 and switched off at 101C.
If none of the aforementioned tests identify the problem and the radiator fan relay is in proper working order, replace the engine control unit.
Component replacement methods
No special measures are necessary in order to replace the radiator fan relay.
Starter motor relay
Engine speed-timing sensorRemoval of the control unit
Loosen the screws (1) and remove the relay supporting bracket (2), disconnect
the connectors (3) and remove the control
unit (4) from the vehicle.
...
Checking the engine timing
Set the engine to the configuration described for the "checking and adjusting
the valve clearances", previously indicated.
Install tool 88765.1188 (G) in the spark plug bore to determine the piston tdc,
the gauges (h) on the tool 88765.1518
And the timing check tool (degree wheel (l) 887 ...
Introduction to the engine control system
The engine control system used on the diavel consists of the following
elements:
Ride-by-wire system (motorised throttle valves with electric actuator,
throttle grip position sensor and throttle valve
position sensor)
One injector per cylinder installed downstream of throttle valve
On ...