Technical Year 2000 Ducato fan running in middle of the night!

[Madmike]

Yeah i've being trying to find a copy , but the truth is i can't even find a record of it even being published . Very strange as the isbn should take me straight to it .
The link won't work , i've tried it , but if you change manual to books you do get a hit , but even here i can't find the book .

I purchased it off ebay , about 4years ago .

Found the longer 13 digit ISBN and have saved a search on Ebay for it anyway. Also found a listing on Amazon but not available

 

[Rclean]

It's part of the pocket manual series by Peter Russek , only one i could find for this model . There's a lot of holes in it , but i'm used to working with diesels . I'm not a professional by any means , and i do come unstuck at times , but it is a little bit of help at times . Problems with it are no pictures at all , diagrams are not always clear , no torque values , and the text can leave large chunks out . For instance , no mention of either a turbo fitting or intercooler for my van . Seems more aimed at the non turbo 2.5/2.8 , But frankly , it's better than nothing .

Just had a quick look on ebay , and theres nothing there , so ;

• www.russek-manuals.co.uk
• ISBN 1-898780-94-3
• Citroen relay/Peugeot boxer/Fiat ducato
• from 1994 2.5/2.8 litre diesel

I’ve got similar issue with my 2.5d.
Fan runs when not used or started in days but now won’t switch off.
It’s the small fan, I tried to see if disconnection of the temp sensor on lower part of radiator would stop the fan.
It does not.
Does that likely point to one of 2 possibles,
1. Relay stuck on.
2. Wire connection break causing fan to run.
The second I’m guessing as a possibility.

 

[Communicator]

I’ve got similar issue with my 2.5d.
Fan runs when not used or started in days but now won’t switch off.
It’s the small fan, I tried to see if disconnection of the temp sensor on lower part of radiator would stop the fan.
It does not.
Does that likely point to one of 2 possibles,
1. Relay stuck on.
2. Wire connection break causing fan to run.
The second I’m guessing as a possibility.

I cannot understand how a broken wire will cause a fan to operate.

May I suggest an earth fault instead.

Does the vehicle have a fan control box on the fan shroud? If yes, then start there, as they are known to suffer problems.

 

[Rclean]

I cannot understand how a broken wire will cause a fan to operate.

May I suggest an earth fault instead.

Does the vehicle have a fan control box on the fan shroud? If yes, then start there, as they are known to suffer problems.

Early at Halfords this morning and picked up a relay 30amp £5.19.
On opening up the relay box the relay being flicked made fan kick in and out, swapped over and no fan. So reconnected the thermostatic sensor and stays off. Short test run today 10 miles to get up to temp and check fan kicks in when it should.
In respect of wire I was only thinking if 2 had connected to cause the feed of bypassing relay and thus causing a circuit. I’m not in anyway trained but is that not what causes the fan to run?
I am hoping it was a dud relay.

 

[airwave]

I’ve got similar issue with my 2.5d.
Fan runs when not used or started in days but now won’t switch off.
It’s the small fan, I tried to see if disconnection of the temp sensor on lower part of radiator would stop the fan.
It does not.
Does that likely point to one of 2 possibles,
1. Relay stuck on.
2. Wire connection break causing fan to run.
The second I’m guessing as a possibility.

First off , these relays are quite robust , but not infallible , so my first response would be , this is unlikely . The simple way to find out , is just swop them out . Both relays are identical .
Now with that said , let me give a brief run down of how this particular circuit works on the majority of vehicles ;
Power is taken from the battery . As it's fairly high power , it's run through something in the region of a 20-30 amp fuse on its way to the relay , usual pin 86 . The feed then reemerges at pin 87 and continues on its way to the actual fan motor/s .

Now let me explain , a relay is very basically a switch , not unlike any other switch you would use to say , turn the lights on . The difference is , it uses power , generally a low amperage current to turn circuits off and on . However , it does have a very important ability , it can safely switch very high amperage currents . It's because of this you will often find them on high powered circuits , such as the aforementioned lights , or to be more specific head lights . It's far easier , and safer to run low current wires around a vehicle than it is high . There are risks to running high amperage cables around , as these cables are often of a heavy cross section to handle both voltage drop , and the pressures of heat .
And anyway as most manual switches operate around the 5-10 amp range , there's not many that will handle 20 amps .

So now lets take a look at the control side of the relay . It takes it's power from fuse 1 , now this is a low amperage circuit protected by a 15 amp fuse , and directly feeds the relay so long as the ignition is turned on , via pin 30 . Notice this means the circuit is permanently powered up , but also notice this breaks with standard practice of placing the switch in the positive side to control the function . In the case of the fans , this is done by the earth . I've no idea the reason why this is the case , but it is common practice .
So on that note , the earth takes a different path , this is taken from the vehicle chassis , probably m47 under the battery , and feeds to the fan thermostat switch fitted in the lower nearside of the radiator . As is common with many older temperature sensors this is whats called a wax switch , as the wax melts this reveals a set contact to complete the circuit , and allow the current to continue on its path back to the relay at pin 85 . This earths the control circuit which in turn , turns the switch on , and so powers the fans up .

Now you say , the fan powers up , even when the vehicle is not in use , so this leaves us with an unusual situation . But not so unusual when you consider the system is permanently powered up . Personally despite finding this unlikely , it does sound like the switch is at fault , or should i say the relay !

As the relay control circuit is ignition controlled , a breakdown here is unlikely .

 

[Communicator]

First off , these relays are quite robust , but not infallible , so my first response would be , this is unlikely . The simple way to find out , is just swop them out . Both relays are identical .
Now with that said , let me give a brief run down of how this particular circuit works on the majority of vehicles ;
Power is taken from the battery . As it's fairly high power , it's run through something in the region of a 20-30 amp fuse on its way to the relay , usual pin 86 . The feed then reemerges at pin 87 and continues on its way to the actual fan motor/s .

Now let me explain , a relay is very basically a switch , not unlike any other switch you would use to say , turn the lights on . The difference is , it uses power , generally a low amperage current to turn circuits off and on . However , it does have a very important ability , it can safely switch very high amperage currents . It's because of this you will often find them on high powered circuits , such as the aforementioned lights , or to be more specific head lights . It's far easier , and safer to run low current wires around a vehicle than it is high . There are risks to running high amperage cables around , as these cables are often of a heavy cross section to handle both voltage drop , and the pressures of heat .
And anyway as most manual switches operate around the 5-10 amp range , there's not many that will handle 20 amps .

So now lets take a look at the control side of the relay . It takes it's power from fuse 1 , now this is a low amperage circuit protected by a 15 amp fuse , and directly feeds the relay so long as the ignition is turned on , via pin 30 . Notice this means the circuit is permanently powered up , but also notice this breaks with standard practice of placing the switch in the positive side to control the function . In the case of the fans , this is done by the earth . I've no idea the reason why this is the case , but it is common practice .
So on that note , the earth takes a different path , this is taken from the vehicle chassis , probably m47 under the battery , and feeds to the fan thermostat switch fitted in the lower nearside of the radiator . As is common with many older temperature sensors this is whats called a wax switch , as the wax melts this reveals a set contact to complete the circuit , and allow the current to continue on its path back to the relay at pin 85 . This earths the control circuit which in turn , turns the switch on , and so powers the fans up .

Now you say , the fan powers up , even when the vehicle is not in use , so this leaves us with an unusual situation . But not so unusual when you consider the system is permanently powered up . Personally despite finding this unlikely , it does sound like the switch is at fault , or should i say the relay !

As the relay control circuit is ignition controlled , a breakdown here is unlikely .

May I offer the following corrections and additions to the above.
1. The input contact to a relay is normally designated 30, and not 86 as stated. 86 is nominally the coil +ve, but Fiat do not rigidly adhere to this.
2. Following from 1. above the coil +ve is normally 86, and not 30 as stated.

I am not sure whether the radiator electrical thermostats are wax operated or not, but I have serious reservations as to the method of operation given. The expansion of the wax as it melts is the property that will be harnessed, as is the case the engine thermostat, or in domestic radiator thermostats.

The fan relays are not always subject to ignition switch control. On my 2.8jtd both relay contact, and coil are permanently connected to 12V. This allows the fans to run after the engine has been switched off.

 

[airwave]

May I offer the following corrections and additions to the above.

Thanks @Communicator , yep i accept that . Bloody pin numbers , i always get them confused , the old grey cells are not what they used to be . Yes your quite correct , i should have checked before writing , but the main purpose was to give a general explanation of how the fan circuit works . Questions regarding issues with the cooling fans are probably the most common subject discussed , on any forum . Normally the answer given is a faulty earth , and in a number of instances , this does actually appear to be the case . My point was to explain how the system works for future reference to others . But lets also not forget , the duke does have its fair share of earth issues . It's just that i couldn't help but notice that Fiat did appear to cover the actual thermostat angle , by using a non conductive plastic .
As regards the operation of the thermostat , yes i accept that as well . It was a much simplified explanation . The solid wax usually contains a contact , or piston , which as the wax melts is allowed to make the contact . Some kind of wax chemistry has to be involved to get different melting temperatures , and i also think springs are involved too . But please don't question me on any of that , as it's way too far over my pay grade for me to understand . Basic operation means the melted wax will reveal a set contact , and so complete the circuit . However , with regards to the 230 , i have seen it stated that the idtd does indeed use wax thermostats . Probably an advert when i was working on my cooling system . I did do a very full , and complete rebuild on my van , which took 18 months to complete , all with the use of the internet .
Modern vehicles have moved on significantly , so they may well have changed the actual thermostat type , but as i wrote somewhere else , i can only comment on vehicles i have actually owned , and that doesn't include variants . I will try to help with older models where i know parts are interchangeable , but as i don't intend to replace any of my current stock , i don't keep up at all with modern developments . Modern vehicles are full of new tech , that i can't understand the reason for , and that's why i shy away from them . Poor excuse i accept , but that is my reasoning . The newest vehicle i own is an 05 , and it's Japanese .

On the final note , yes i accept that too . However on my van , as i stated , the fans will if working , which is rare also shut down .

 

[Communicator]

Hi airwave,
The purpose of my post was mainly to correct the errors, and avoid spreading confusion to others.
If indeed wax operated thermastatic switches are used in the fan control, then I still think that this will be in the form of sealed capsules with an ouput piston operating mechanical contacts designed to have a snappy action. A spring return for will be necessary for the piston. As to adjusting the wax melting point, perhaps various blends of wax are used.
Consider the multitude of operating points for the thermostats, used in various engine cooling systems.

 

[airwave]

Hi airwave,
The purpose of my post was mainly to correct the errors, and avoid spreading confusion to others.
If indeed wax operated thermastatic switches are used in the fan control, then I still think that this will be in the form of sealed capsules with an ouput piston operating mechanical contacts designed to have a snappy action. A spring return for will be necessary for the piston. As to adjusting the wax melting point, perhaps various blends of wax are used.
Consider the multitude of operating points for the thermostats, used in various engine cooling systems.

Yep i totally accept that . I simply didn't feel it added anything to the explanation , just begin to complicate it , and lets be honest here , it was long enough as it was . People tend to shut down if something is too long or complicated , and look for something easier to understand . I tried to lighten it up to make it interesting .
The pin numbers was a really bad mistake , that's one job still on the to do list . I need to find the control earth , so i can remote activate it . Right now i have my head in the fridge . It's a bit more than a standard service , i've found a couple of serious problems that need attention , but that is a whole different story .
Yes indeed , but like i said don't quiz me on that subject . In my opinion a spring would have to be used to open the contact again , else the wax would freeze the contact in place as it solidified , and yes that is also my opinion in regard to blends of wax . But these would be purely based on opinion , not fact . These thermostats are used in a variety of uses and temperatures . In fact , we discussed two different temperature ranges on this thread for this particular vehicle , earlier . I seem to recall the sensors in the thermostat housing are also wax operated , and i know my Citroen uses them in the cooling circuit as well . That's 6 years older . I would further agree with the capsules too . It would be far simpler trying to time multi temperature contacts on a dual operation thermostat , also such as we have in this case .