2004 1.6 Engine cooling fan not working

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My Name: krasny

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Posts: 10
Joined: Sat Jun 27, 2020 9:23 pm
Model: C3 2002-2005, Original shape model
Year: 2004 (04)
Engine Size: 1.6
Fuel Type: Petrol
Mileage: 125000
Gearbox: Manual 5 speed
DPF: No
LHD or RHD: LHD (Europe)
Engine name: TU3 (75 PS)
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Hi there!

I have a 2004 1.6 C3 and started by noticing that the A/C stopped working recently. I read that the cause can be the cooling fan (the compressor and the inside fan works) and noticed that the cooling fan doesn't work. It does not spin, I checked the coolant temperature with torque and it is hitting over 90ºC and does not spin not even with the A/C on. I tested all the fuses and seems to be ok and and relay (which is on top of the fan) is also ok. I read about a resistance with a thermo fuse but I could't find it on my car, this one:
photo_2020-06-28_00-11-53.jpg
I also tested the fan and works.

Any ideas of what can be failing?
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My Name: Arfur Dent

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Model: C3 2002-2005, Original shape model
Year: 2002 (52)
Engine Size: 1.4 (16v)
Fuel Type: Diesel
Mileage: 100000
Trim Level: Exclusive
Gearbox: Manual 5 speed
DPF: No
LHD or RHD: RHD (UK)
Engine name: DV4 16-valve diesel (90 PS)
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You can test the fan with lexia tool so you test the whole system and not just the fan motor.

That will give you a fuller picture, but it won't find the fault.

but it will read all the codes so that may give you some hints on what is stopping the fan from running.
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My Name: krasny

Contributor
Posts: 10
Joined: Sat Jun 27, 2020 9:23 pm
Model: C3 2002-2005, Original shape model
Year: 2004 (04)
Engine Size: 1.6
Fuel Type: Petrol
Mileage: 125000
Gearbox: Manual 5 speed
DPF: No
LHD or RHD: LHD (Europe)
Engine name: TU3 (75 PS)
Has thanked: 2 times

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Thank you Arfur for your reply.

Sadly I don't have a Lexia cable to do a diagnosis on the car, that's why I'm trying to find the problem "manually". However I can't find anything wrong and it seems that the cooling system is different than other c3 models.
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My Name: Arfur Dent

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Posts: 3308
Joined: Sat Jul 23, 2011 3:47 pm
Model: C3 2002-2005, Original shape model
Year: 2002 (52)
Engine Size: 1.4 (16v)
Fuel Type: Diesel
Mileage: 100000
Trim Level: Exclusive
Gearbox: Manual 5 speed
DPF: No
LHD or RHD: RHD (UK)
Engine name: DV4 16-valve diesel (90 PS)
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The C3 has a computer controlled cooling system., So if you can't test the computer and use the onboard diagnostics using lexia, you are going to have a very difficult time and quite possibly a complete waste of that time.

Good luck finding the problem manually.
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My Name: krasny

Contributor
Posts: 10
Joined: Sat Jun 27, 2020 9:23 pm
Model: C3 2002-2005, Original shape model
Year: 2004 (04)
Engine Size: 1.6
Fuel Type: Petrol
Mileage: 125000
Gearbox: Manual 5 speed
DPF: No
LHD or RHD: LHD (Europe)
Engine name: TU3 (75 PS)
Has thanked: 2 times

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In that case I'll look for a lexia adapter and try to find the problem.

Thank you again!
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My Name: Ozvtr

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Model: C3 2002-2005, Original shape model
Year: 2003 (53)
Engine Size: 1.4 (8v)
Fuel Type: Petrol
Mileage: 80000
Trim Level: Other
Gearbox: Automatic PRND
DPF: No
LHD or RHD: RHD
Engine name: TU3 (75 PS)
Location: Brisbane, Australia.
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How are you measuring that the coolant temp is over 90'? The normal operating temperature range of the coolant at the outlet is about 85-90 degrees. So how far over 90' are we talking?
On the top of the thermostat housing (where the top radiator hose goes to the radiator) you will see a green electrical plug. This is the coolant out let temperature sensor. If you disconnect the plug from the sensor the thermo fan should start to run after 10-20 seconds. The temp indicator on the dash will show all the bars and the engine may run a bit rough. Note; doing this will log an error entry in the engine ECU but it will not bring on the check engine light. If the thermo fan doesn't come on then you have a fault.
The engine ECU runs the thermo fan proportionally to the A/C high side pressure. The higher the pressure the faster the fan. If the air con is not under much of a load or there is low gas in the system the fan might not run but the compressor still might cut in. Is the aircon cold? If it's not cold it might be low on gas and that might be why the fan doesn't come on.
Hope this helps.

EDIT; D'oh! actually went back and READ you post (sorry). You obviously have some sort of OBDII code reader to read the temp.
If you have tested the fan (and it works) then you are most likely low or out of gas in the A/C system. Take one of the valve caps off the Schrader valves on the aluminium lines and use a thin object to push the centre pin of the valve. They are exactly like a tyre valve. If you have enough gas it will come out with quite a bit of force, so be warned!!! Just pick one and press the centre FOR A VERY SHORT TIME! If nothing happens or you just get a slight hiss, it's out of gas.
My Name: krasny

Contributor
Posts: 10
Joined: Sat Jun 27, 2020 9:23 pm
Model: C3 2002-2005, Original shape model
Year: 2004 (04)
Engine Size: 1.6
Fuel Type: Petrol
Mileage: 125000
Gearbox: Manual 5 speed
DPF: No
LHD or RHD: LHD (Europe)
Engine name: TU3 (75 PS)
Has thanked: 2 times

Post

Ozvtr wrote: Mon Jun 29, 2020 1:06 am How are you measuring that the coolant temp is over 90'? The normal operating temperature range of the coolant at the outlet is about 85-90 degrees. So how far over 90' are we talking?
On the top of the thermostat housing (where the top radiator hose goes to the radiator) you will see a green electrical plug. This is the coolant out let temperature sensor. If you disconnect the plug from the sensor the thermo fan should start to run after 10-20 seconds. The temp indicator on the dash will show all the bars and the engine may run a bit rough. Note; doing this will log an error entry in the engine ECU but it will not bring on the check engine light. If the thermo fan doesn't come on then you have a fault.
The engine ECU runs the thermo fan proportionally to the A/C high side pressure. The higher the pressure the faster the fan. If the air con is not under much of a load or there is low gas in the system the fan might not run but the compressor still might cut in. Is the aircon cold? If it's not cold it might be low on gas and that might be why the fan doesn't come on.
Hope this helps.

EDIT; D'oh! actually went back and READ you post (sorry). You obviously have some sort of OBDII code reader to read the temp.
If you have tested the fan (and it works) then you are most likely low or out of gas in the A/C system. Take one of the valve caps off the Schrader valves on the aluminium lines and use a thin object to push the centre pin of the valve. They are exactly like a tyre valve. If you have enough gas it will come out with quite a bit of force, so be warned!!! Just pick one and press the centre FOR A VERY SHORT TIME! If nothing happens or you just get a slight hiss, it's out of gas.
Thank you very much for your detailed answer!

I didn't use the car (thank you COVID) and ordered a Lexia 3 to be able to do more tests since the ODB was not very useful. I tried today with the Lexia 3 and diagbox and found that there are no errors at all in the injection section and tried the two fan tests, low speed and full speed. The full speed works as expected and the fan runs but the problem is the low speed: the test seems to work and lexia shows as sucess but the fan doesn't run at all. I also can hear a click from the motor fusebox. I did not try yet to disconnect the water temp sensor, but I can try tomorrow.

I watch this video of ECU reprogramming: https://www.youtube.com/watch?v=ddFCvxpQE3E but after the lexia tests i don't think that reprogramming can fix the problem since it seems that the computer is turning on the fan but is not spinning (mine is ME744 version 2221). Any ideas if there is any resistor for the low speed of the fan? I found it for other models but not for my model.

Tomorrow I'll test the gas pressure (I never thought it can be that easy to test it) but I'm much more concerned about the fan than the A/C, last year I had to change the cylinder head gasket on my Toyota due to a overheat and it was expensive as hell.

thank you again for your help!
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My Name: Ozvtr

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Posts: 942
Joined: Wed Jul 10, 2019 3:31 am
Model: C3 2002-2005, Original shape model
Year: 2003 (53)
Engine Size: 1.4 (8v)
Fuel Type: Petrol
Mileage: 80000
Trim Level: Other
Gearbox: Automatic PRND
DPF: No
LHD or RHD: RHD
Engine name: TU3 (75 PS)
Location: Brisbane, Australia.
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krasny wrote: Sat Jun 27, 2020 10:17 pm Hi there!

I have a 2004 1.6 C3 and started by noticing that the A/C stopped working recently. I read that the cause can be the cooling fan (the compressor and the inside fan works) and noticed that the cooling fan doesn't work.
I took it that you were more concerned with the aircon in the beginning but never mind.

There seems to be a great number of versions of thermo fans and speed controllers and I don't know why. Some have variable speed, some are two speed, some use fixed resistors and some use electronic controllers. However, to my knowledge the 1.6 (NFU) engine has a variable speed controller. That speed controller is physically part of the motor in the fan assembly. Now I have not been able to track down a circuit diagram which has both a relay and an electronic speed controller. However EXIBIT A: the relay in my Citroen C2 failed and occasionally, for no reason, with the car locked and not running, the thermo fan would run at full speed! This tells me that the relay bypasses the speed controller and runs the fan when activated. In this case the contacts inside the relay were loose and randomly making contact! So if the speed controller is not working but the relay is, this explains why you get full speed but not low speed.
EXIBIT B: When I was getting one of my C3's back on the road I pulled the thermo fan housing off the radiator and found the insulation on the wiring was disintegrating! Particularly the smaller wires going the speed controller.
So my best guess would be a failure of the variable speed controller on the motor/fan housing BUT I cant prove that! The final proof would be to put an oscilloscope on the PWM (Pulse Width Modulation) line going to the fan speed controller and make sure the controller IS receiving pulses from the engine ECU but I doubt you have the equipment to do that.
The "actuator test" of the fan should run the fan at low speed even if there is no gas in the system. It WONT let you run the compressor with no gas and the engine running (I tried it) but it will pull the clutch in without the engine running ( just FYI).
If you buy another fan unit from a breaker, how do you know it's not faulty too?

Sorry, that's all I've got for the minute. Something to think about.
My Name: krasny

Contributor
Posts: 10
Joined: Sat Jun 27, 2020 9:23 pm
Model: C3 2002-2005, Original shape model
Year: 2004 (04)
Engine Size: 1.6
Fuel Type: Petrol
Mileage: 125000
Gearbox: Manual 5 speed
DPF: No
LHD or RHD: LHD (Europe)
Engine name: TU3 (75 PS)
Has thanked: 2 times

Post

Ozvtr wrote: Tue Jul 28, 2020 12:53 am I took it that you were more concerned with the aircon in the beginning but never mind.

There seems to be a great number of versions of thermo fans and speed controllers and I don't know why. Some have variable speed, some are two speed, some use fixed resistors and some use electronic controllers. However, to my knowledge the 1.6 (NFU) engine has a variable speed controller. That speed controller is physically part of the motor in the fan assembly. Now I have not been able to track down a circuit diagram which has both a relay and an electronic speed controller. However EXIBIT A: the relay in my Citroen C2 failed and occasionally, for no reason, with the car locked and not running, the thermo fan would run at full speed! This tells me that the relay bypasses the speed controller and runs the fan when activated. In this case the contacts inside the relay were loose and randomly making contact! So if the speed controller is not working but the relay is, this explains why you get full speed but not low speed.
EXIBIT B: When I was getting one of my C3's back on the road I pulled the thermo fan housing off the radiator and found the insulation on the wiring was disintegrating! Particularly the smaller wires going the speed controller.
So my best guess would be a failure of the variable speed controller on the motor/fan housing BUT I cant prove that! The final proof would be to put an oscilloscope on the PWM (Pulse Width Modulation) line going to the fan speed controller and make sure the controller IS receiving pulses from the engine ECU but I doubt you have the equipment to do that.
The "actuator test" of the fan should run the fan at low speed even if there is no gas in the system. It WONT let you run the compressor with no gas and the engine running (I tried it) but it will pull the clutch in without the engine running ( just FYI).
If you buy another fan unit from a breaker, how do you know it's not faulty too?

Sorry, that's all I've got for the minute. Something to think about.
Thank you again for your thoughts!

My impression also is that the fan has some kind of problem. I also read about problems with the contacts getting rust and no longer working for other people so maybe that's the problem (it is very old and also was quite dirty). I have a very old oscilloscope (since electronics is one of my hobbies) and I can test for the signal, but I don't know which wire is. Do you know which one is the PWM signal? I guess it's one of the three pin connector. Attached is a picture of the connectors in my unit.

About getting a replacement: I had the same thought as you, if I buy a used fan from a breaker I will not now if fan has the same problem or if I miss the diagnosis and returns are usually difficult/impossible. However I could find it online from a seller in my city for about 40€. I also found a non-oem replacement in amazon for about 100€ new, which it is much more but I will know for sure that if doesn't work is not because the part is bad. Considering that any repair shop would be much much more expensive I think I can afford to buy the new one.

thank you again!
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My Name: Ozvtr

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Posts: 942
Joined: Wed Jul 10, 2019 3:31 am
Model: C3 2002-2005, Original shape model
Year: 2003 (53)
Engine Size: 1.4 (8v)
Fuel Type: Petrol
Mileage: 80000
Trim Level: Other
Gearbox: Automatic PRND
DPF: No
LHD or RHD: RHD
Engine name: TU3 (75 PS)
Location: Brisbane, Australia.
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Been thanked: 252 times

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krasny wrote: Tue Jul 28, 2020 6:09 pm Do you know which one is the PWM signal? I guess it's one of the three pin connector. Attached is a picture of the connectors in my unit.
The short answer is no. But if you have a knowledge of electronics you should be able to probe the 3 pin connector and find the PWM signal (if it's there).By looking at the picture you can see the red wire (in the 3 pin connector) goes to the relay, so the black and blue wires would go to the speed controller. By convention the black is usually ground, leaving the blue wire as PWM. Unfortunately the wire colours in the genuine fan assembly wont be the same. The big 2 pin connector will be the high current supply for the fan.
The engine ECU's seem to be pretty robust and I have not heard of one failing. So my money is on the fan assembly and there might be a good reason why there is an aftermarket fan assembly available?
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