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Ducato 2003 2.3 JTD - cooling fans not cutting in


bob b

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I'd appreciate some help here please. The cooling fans are not kicking in when required. They work perfectly fine when I switch on the a/c, so I know the fans are okay. I'm assuming that the thermostatic fan switch is 'dicky'. Could somebody supply a wiring diagram of the relevant circuit? Even better - tell me where the location of 'dicky' switch actually is!

 

Many thanks in anticipation.

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The sensor is usually close to the top of the radiator it will have three wires to it. The upper fan is designed to come on first and the lower one above a set temp. If you touch the wires two of the wires together with the ignition on they should work if its the sensor.

You may have to experiment which is which, if you touch the two fan ones nothing will happen.

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True re how often they cut in, we were in Naples stuck in traffic for three hours (apparently this is normal) temp in excess of 28c they only cut in then first time I could remember them doing so. A diesel is most efficient when running at higher temp so unless you see the temp. Gauge climbing up to the red you may just have not been hot enough to need them?
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747 - 2021-07-01 4:17 PMI had a 2.8 jtd pulling a 5 ton motorhome and never heard the fans cut in once. I don't think you have a problem .... unless you are heading for the Sahara. :D

I was on my way to Dorset in slow moving traffic on the A27 a few weeks ago on the hottest day of the year (to date). The temperature gauge went off the scale and the coolant was boiling. The fans did not cut in. When the a/c is switched on - then the fans work okay. I think I have a problem!

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bob b - 2021-07-01 5:23 PM

 

747 - 2021-07-01 4:17 PMI had a 2.8 jtd pulling a 5 ton motorhome and never heard the fans cut in once.I don't think you have a problem .... unless you are heading for the Sahara. :D

I was on my way to Dorset in slow moving traffic on the A27 a few weeks ago on the hottest day of the year (to date). The temperature gauge went off the scale and the coolant was boiling. The fans did not cut in. When the a/c is switched on - then the fans work okay. I think I have a problem!

I think you have! 8-) Hope you get it sorted.

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bob b - 2021-07-01 1:48 PM

 

I'd appreciate some help here please....

Suggest you ask about this on the Fiat Forum.

 

https://www.fiatforum.com/ducato/

 

There is a fair amount of online discussion about Ducato radiator fans not coming on or not going off, but (as far as I can see) not directly relating to the 2.3litre motor in your vintage of Ducato.

 

https://tinyurl.com/dyvcbzfx

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Derek Uzzell - 2021-07-02 7:21 AM
bob b - 2021-07-01 1:48 PMI'd appreciate some help here please....
Suggest you ask about this on the Fiat Forum.https://www.fiatforum.com/ducato/There is a fair amount of online discussion about Ducato radiator fans not coming on or not going off, but (as far as I can see) not directly relating to the 2.3litre motor in your vintage of Ducato.https://tinyurl.com/dyvcbzfx

Thanks for that Derek.

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weldted - 2021-07-02 9:11 AMIf you were to try what I previously suggested you would know whether it is the sender or not which would be the best place to start.

The weather beat me yesterday ....... bit of a scramble to get the tools under cover. I will try that first. Thanks for the tip.

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I have an elearn pdf of the 'engine cooling' that you may find useful. I cannot attach it as it is over the 100kb limit [ it is 302kb] of the forum. I am happy to send it if there is a way?
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bob b - 2021-07-01 1:48 PM

 

I'd appreciate some help here please. The cooling fans are not kicking in when required. They work perfectly fine when I switch on the a/c, so I know the fans are okay. I'm assuming that the thermostatic fan switch is 'dicky'. Could somebody supply a wiring diagram of the relevant circuit? Even better - tell me where the location of 'dicky' switch actually is!

 

Many thanks in anticipation.

Bob,

 

I do not have experience of aircon on a Ducato, but your post above has me puzzled.

 

I owned a Talbot Express, again without aircon, for many years. On that vehicle the cooling fans were controlled, as referenced to by Weldted, by a double contact thermostat mounted on the RHS side of the radiator.

 

On my current Ducato, which is a 2006 x244 2.8 JTD, the cooling fans are controlled by the ECU, which receives engine temperature information from a sensor mounted on the engine thermostat housing. There is a separate sensor/thermostat for the temperature gauge and do not use warning light.

 

There were considerable changes involved in the introduction of the common rail (JTD) engines in year 2000, and again with the change from x230, to x244 models in 2003? I think that perhaps your vehicle is an x230, so wiring will differ from my x244.

 

I have checked my copy of Fiat eLearn which is applicable to my vehicle, and I cannot find any suggestion that the engine cooling fans are switched on by the aircon. Nothing in the descriptive text, and no connection to the ECU in the diagrams. We have two other vehicles (not Fiat) which have aircon, and I have not noticed this initiation of the cooling fans via the aircon.

 

In view of the above, it would help if you could confirm your statement, that the engine cooling fans are switched on when the aircon is selected.

 

I am attaching copies of eLearn based engine sensor locations, and engine temperature sensor for the ECU. While these are relate to an x244 2.3 JTD, I hope that they will also make sense for your vehicle.

 

In order to help others please post the final solution.

 

Alan

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The file would not attach as it is 101KB. So in plain text, in my copy of eLearn which relates to the x244 version of the Ducato, the 2.3 JTD the temperature sensors are located at the front RH end of the engine, that is on your left as you look into the engine bay. The upper sensor is for the gauge, and the lower one for the ECU.

 

If you want that in pdf format, I can only suggest that you PM me with your email address.

 

Alan

Ducato 2.3 JTD Coolant Sensor.pdf

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Alanb - 2021-07-02 1:49 PM

 

On my current Ducato, which is a 2006 x244 2.8 JTD, the cooling fans are controlled by the ECU, which receives engine temperature information from a sensor mounted on the engine thermostat housing. There is a separate sensor/thermostat for the temperature gauge and do not use warning light.

 

Alan

Slightly off topic but looking at my (2003) 2.8 JTD (from memory), I recall that the sensor connected to the thermostat housing is for the temperature gauge – disconnect it and the gauge falls to zero (been there, done that). I’ve not spotted another. However there is a sensor for engine oil temperature which connects to the ECU and I had assumed consequently is responsible for determining whether or not to operate the radiator cooling fans. Some way of getting hold of the elearn wiring diagram you mentioned would be handy.

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rayc - 2021-07-02 10:33 AMI have an elearn pdf of the 'engine cooling' that you may find useful. I cannot attach it as it is over the 100kb limit [ it is 302kb] of the forum. I am happy to send it if there is a way?

Many thanks Ray. PM sent.

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BruceM - 2021-07-02 2:23 PM

 

Alanb - 2021-07-02 1:49 PM

 

On my current Ducato, which is a 2006 x244 2.8 JTD, the cooling fans are controlled by the ECU, which receives engine temperature information from a sensor mounted on the engine thermostat housing. There is a separate sensor/thermostat for the temperature gauge and do not use warning light.

 

Alan

Slightly off topic but looking at my (2003) 2.8 JTD (from memory), I recall that the sensor connected to the thermostat housing is for the temperature gauge – disconnect it and the gauge falls to zero (been there, done that). I’ve not spotted another. However there is a sensor for engine oil temperature which connects to the ECU and I had assumed consequently is responsible for determining whether or not to operate the radiator cooling fans. Some way of getting hold of the elearn wiring diagram you mentioned would be handy.

Bruce,

 

Browse this link, but do be aware that eLearn is not devoid of errors, also some of the descriptions are cropped short.

 

Alan

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Alanb - 2021-07-02 1:49 PM
bob b - 2021-07-01 1:48 PM

 

I'd appreciate some help here please. The cooling fans are not kicking in when required. They work perfectly fine when I switch on the a/c, so I know the fans are okay. I'm assuming that the thermostatic fan switch is 'dicky'. Could somebody supply a wiring diagram of the relevant circuit? Even better - tell me where the location of 'dicky' switch actually is! Many thanks in anticipation.

Bob, I do not have experience of aircon on a Ducato, but your post above has me puzzled. I owned a Talbot Express, again without aircon, for many years. On that vehicle the cooling fans were controlled, as referenced to by Weldted, by a double contact thermostat mounted on the RHS side of the radiator. On my current Ducato, which is a 2006 x244 2.8 JTD, the cooling fans are controlled by the ECU, which receives engine temperature information from a sensor mounted on the engine thermostat housing. There is a separate sensor/thermostat for the temperature gauge and do not use warning light. There were considerable changes involved in the introduction of the common rail (JTD) engines in year 2000, and again with the change from x230, to x244 models in 2003? I think that perhaps your vehicle is an x230, so wiring will differ from my x244.I have checked my copy of Fiat eLearn which is applicable to my vehicle, and I cannot find any suggestion that the engine cooling fans are switched on by the aircon. Nothing in the descriptive text, and no connection to the ECU in the diagrams. We have two other vehicles (not Fiat) which have aircon, and I have not noticed this initiation of the cooling fans via the aircon. In view of the above, it would help if you could confirm your statement, that the engine cooling fans are switched on when the aircon is selected. I am attaching copies of eLearn based engine sensor locations, and engine temperature sensor for the ECU. While these are relate to an x244 2.3 JTD, I hope that they will also make sense for your vehicle. In order to help others please post the final solution. Alan

Hi Alan,

 

I'm muddling along in the dark here! I haven't got a workshop manual (not available?), so I don't know what triggers the fans. I'm assuming its some kind of thermostatic switch? - but where is the location! If I knew where it is I could test it. There must be a sensor somewhere that monitors the coolant and switches on the fans.

 

I've rebuilt engines in the past, so I'm not a 'mechanical  novice'. The cooling fans have always cut in immediately I turn on the A/C. I'll certainly post the outcome of this saga to help others in the same situation ...... it irritates me when others don't bother.

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I’m not an expert but a few observations.

 

1/ I don’t understand what turning on air con has to do with the radiator coolant fans. I would expect turning on air con to simply engage the aircon compressor and turn on the cab fan.

 

2/ On by 2.8 JTD the radiator coolant fans are controlled by the ECU. The reliable way to test that part of the circuit is to plug an analyser into the OBD port and manually switch them on and off. It’s how I checked mine. If they do not switch on I’d next check fuses with a multimeter – ie not by eye. If the fuses are ok I’d ask for more forum assistance.

 

3/ If ‘2’ above comes out ok then the next bit to investigate is temperature sender to ECU circuit. The way I would check that is to get the engine up to working temperature and then with the OBD port analyser check what temperature the ECU is registering. If no/a-too-low temperature is registering then in the first instance I’d change the sender and/or check everything is still connected.

 

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Alanb - 2021-07-02 4:56 PM

 

Bruce,

 

Browse this link, but do be aware that eLearn is not devoid of errors, also some of the descriptions are cropped short.

 

Alan

Thanks Alan, that's a great resource. However the wiring diagram is displaying as below, I suspect you do not have the same issue. I've tried it on several browser types. Are you aware of a work around?

1842995268_ScreenHunter_01Jul_0218_51.jpg.a2ea3bf4d4aeaa2ad609f45bb1ae1a47.jpg

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BruceM - 2021-07-02 6:55 PM

 

Alanb - 2021-07-02 4:56 PM

 

Bruce,

 

Browse this link, but do be aware that eLearn is not devoid of errors, also some of the descriptions are cropped short.

 

Alan

Thanks Alan, that's a great resource. However the wiring diagram is displaying as below, I suspect you do not have the same issue. I've tried it on several browser types. Are you aware of a work around?

Sorry Bruce,

 

Some of the diagrams do come out like that, and I had not checked that the problem affected the cooling system schematic. My work around is to use the CD that I purchased from Ebay, and which my geekish son has mounted on my SSD, so nearly as quick as from 4cardata. Disadvantage is that converting directly to .pdf results in barely readable text, and I can't link to it. My workaround to the latter problem is more involved, but once I have the file in pdf format, I can add device names and notes.

 

Alan

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Bob,

 

I also am on a steep learning curve.

 

After further searching on eLearn, I have now discovered the link between switching on the aircon, and the cooling fans being started. The aircon ON signal is routed via several sensors which are shown on the "Climate Control System - Compressor Engagement" diagram E6021, to the ECU which controls the fans.

 

Since you confirmed the operation of the cooling fans in your initial post, and the description of the engine temperature sensor states that the sensors resistance drops with temperature, a high resistance or faulty sensor/connection must be worthy of investigation.

 

Alan

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Alanb - 2021-07-02 9:54 PM

 

Bob,

 

I also am on a steep learning curve.

 

After further searching on eLearn, I have now discovered the link between switching on the aircon, and the cooling fans being started. The aircon ON signal is routed via several sensors which are shown on the "Climate Control System - Compressor Engagement" diagram E6021, to the ECU which controls the fans.

 

Since you confirmed the operation of the cooling fans in your initial post, and the description of the engine temperature sensor states that the sensors resistance drops with temperature, a high resistance or faulty sensor/connection must be worthy of investigation.

 

Alan

Could this be a symptom of a failing engine to chassis earth strap? ie High resistance?

 

Keith.

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