RBus59 Posted December 6, 2015 Share Posted December 6, 2015 Hello, Got out of the S-Max 2.0Litre Diesel tonight, fan running....not uncommon after a high speed run or time spent in traffic - thought nothing of it. 10 minutes later went back out to car.....Fan still running.....odd as the journey we had just made was only 5 minutes and not high speed. Started car again - let it idle - wanted to see if it would correct itself....it did not. Decided to pull the hood and disconnect the fuse......F5 - 60 ~Amps.....found out this is the type which have a bolted in type of fuse.....could not easily remove it so disconnected battery and left it for 20 minutes. Re-attached it and the fan kicked in straight away. So in my mind I am looking at a faulty fuse (unlikely as this would go open circuit).....faulty fan relay (located on side of fan and looks to be honest like a miniature ECU) or faulty engine coolant sensor. Any suggestions what else it could be? Am I safe to pull the bolted type fuse at 60 amps so the wife can drive the car about (5 mile journeys to and from school only....no real traffic).....?.....or should I pull the wiring from the fan where it plus into the relay on the radiator fan cowl - just so the car can be used while I do a bit more investigation (Hopefully someone on here will know what to do more than me !!). Look forward to hearing from you guy's. Many Thanks, Chris Quote Link to comment Share on other sites More sharing options...
MONDEO TXS 2.2 Posted December 6, 2015 Share Posted December 6, 2015 DPF regeneration ? 1 Quote Link to comment Share on other sites More sharing options...
iantt Posted December 6, 2015 Share Posted December 6, 2015 I would pull the conector off the fan, easier than trying to unbolt the fuse if when reconnecting battery tommorow Quote Link to comment Share on other sites More sharing options...
RBus59 Posted December 6, 2015 Author Share Posted December 6, 2015 Can you tell me more about the DPF regeneration cycle? I didn't think my 2.0TDCI Duratorq had a DPF fitted? But welcome to be corrected !! If I pull off the lead to the fan.....will this damage anything to the ECU? I would assume not - but its been a long time since I had my head under a bonnet and technology has changed a lot. Any ideas how I can check the operation of the Coolant Temperature Sensor......or where it is on this engine as I still believe the ECU needs to get a temperature signal from somewhere and I am assuming this is from the CTS or does it come from the thermostat? Quote Link to comment Share on other sites More sharing options...
iantt Posted December 6, 2015 Share Posted December 6, 2015 You wont damage anything by pulling plug off, as for temp sensor it should be located on a plastic housing where thermostat is located, it is buried sonewhat and awkward to get to sensor I think, could wrong. If you have multimeter you could check the reference voltage,(5v) and resistance when cold, should be around 10kohms. Then sensor does go via the pcm for the temp guage so unless thats reading incorrect, then I doubt the sensor is at fault. Quote Link to comment Share on other sites More sharing options...
RBus59 Posted December 6, 2015 Author Share Posted December 6, 2015 Hello again......more update - just had AA out to it. Pulled off plug to the top of the module that sits on the side of the fancowl (still not sure if this is a relay or power unit or a mini ECU - it looks like a relay in some postings for other Ford engines.... can anyone clarify?)......... anyway with top plug disconnected the fan stopped working..... which was a result ! BUT - the connector is getting a voltage from somewhere saying 'run the fan'. The relay seems to be working correctly, and there are no fault codes stored in the ECU (AA man checked this for me which was good of him). This now leaves me with a vehicle which at least can be driven for a few days - but I now have to try and find out what is giving the signal to the fan to operate. DPF has been mentioned - but the regent cycle would have been disturbed and also the CTS showed only 20 degrees - so I cannot see how this would be telling the fan to work. Would a short circuit cause this to happen......... any thoughts on what could be telling the fan to run would be appreciated.... otherwise its a costly visit to Ford that REALLY worries me at this time of year :-( Thanks, Chris Quote Link to comment Share on other sites More sharing options...
iantt Posted December 6, 2015 Share Posted December 6, 2015 Its a mini ecu of sorts, basically you have thick live and earth wires and a thin signal wire that main ecu tells fan to work and at what speed, so either the fan control unit ( mini ecu ) is internally faulty or the main pcm is giving signal wire incorrect signal . Im betting its the fan control unit faulty. Quote Link to comment Share on other sites More sharing options...
RBus59 Posted December 7, 2015 Author Share Posted December 7, 2015 Thank you - but if the mini ECU is disconnected as it is now...... how could this be the fault? The wire feeding to the top of the mini ECU is getting its signal from the relay in the main fusebox- which I'm guessing is coming from the main ECU ? Do you have a wiring diagram or schematic to show how the circuit works? Quote Link to comment Share on other sites More sharing options...
iantt Posted December 7, 2015 Share Posted December 7, 2015 Im sure the multiplug thats been disconnected also has the power and earth so they have but cut to stop fan working, got a diagram somewhere, see what I can post up later for you , it is straight forward circuit. Quote Link to comment Share on other sites More sharing options...
RBus59 Posted May 21, 2017 Author Share Posted May 21, 2017 Just to close the loop on this one, the mini ecu for the fan was at fault, but Ford will not sell one independently.....therefore its a fan and new mini ecu.....£300 later an d the car is running happily again. Quote Link to comment Share on other sites More sharing options...
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