Interior heater fan not working

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My Name: C3driver52

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Model: C3 2002-2005, Original shape model
Year: 2003 (03)
Engine Size: 1.4 i
Fuel Type: Petrol
Mileage: 79984
Trim Level: VTR+
Gearbox: Manual 5 speed
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Engine name: TU3 (75 PS)
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And then I wanted to ask if you think this control
I don't know by looking at them, but I do know that the petrol and diesels engined car have different wiring for the air con and use different and incompatible heater control panels. The difference can be spotted by counting the number of connections on the heater plug.

If the plug matches yours (on the other side) then you could be lucky, its worth a try ?
My Name: cineo

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Model: C3 2002-2005, Original shape model
Year: 2003 (03)
Engine Size: 1.4
Fuel Type: Diesel
Mileage: 125000
Trim Level: VTR+
Gearbox: Manual 5 speed
DPF: No

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Hi C3driver52. I'm sorry but I still need your help. I could find the spare part but the fan
still does not work! I've checked all the fuses! What could it be now? :(
My Name: 927465

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Joined: Mon Jan 13, 2014 7:06 pm
Model: C3 2002-2005, Original shape model
Year: 2003 (03)
Engine Size: 1.4 (8v)
Fuel Type: Diesel
Mileage: 110000
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Gearbox: Manual 5 speed
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It sounds like you have the same car as me. I'd like to think I am quite knowledgeable on this subject, having recently fixed my blower problems.

Can you give me a breakdown of your scenario? Hopefully I can help. What have you replaced, what have you checked etc. Assuming you have the same car as me, I can probably find my scribbles and update them further so you make sense of them. Note I don't have the full circuit as I only reverse engineered what I needed to. Haynes manual was helpful, but wasn't entirely accurate and/or definitive.
My Name: cineo

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Posts: 15
Joined: Thu Nov 21, 2013 12:01 pm
Model: C3 2002-2005, Original shape model
Year: 2003 (03)
Engine Size: 1.4
Fuel Type: Diesel
Mileage: 125000
Trim Level: VTR+
Gearbox: Manual 5 speed
DPF: No

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Hello! Thank you for the help that you give me. The fan works because I connected the pin a4 to the ground
and it turn on when the engine running. Speaking with other people I knew were defective panel but not him!
The problem is something else! How did you solve it?
My Name: 927465

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Posts: 11
Joined: Mon Jan 13, 2014 7:06 pm
Model: C3 2002-2005, Original shape model
Year: 2003 (03)
Engine Size: 1.4 (8v)
Fuel Type: Diesel
Mileage: 110000
Trim Level: Desire
Gearbox: Manual 5 speed
DPF: No

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If by grounding pin A4, the fan then blows air, then the fuse, fusebox and enabling of 12V(which is only enabled when the engine is running) are all working. This is good news as the rest is relatively simple.

Note the enabling of 12V was the only bit I didn't reverse engineer as it was working for me too.

See post: https://citroenc3owners.com/citroen-c3-q ... -t879.html to see the scenario that I had. I very much suspect you have a similar or the same problem.

Did you get a replacement control unit? Do you have the capability of confirming the replacement control unit works? Do you know how to remove the fan motor? Do you know how to use a multimeter? I can explain how to do all of this, although removing the fan is a bit of a pain.

Does the fan work on setting 4 of the replacement control unit?

Basically my fan had gone low resistance(note it would still blow air fine with 12V across it, it was just using lots of current and hence the reason it blew the control unit and resistor pack). This then blew my control unit and my resistor pack. I can send you a drawing of how its all connected if that will help you.

I got a replacement fan motor, replacement control unit and a replacement resistor pack. With the exception of wires(which might be burnt out, but I doubt it) there is nothing else to the circuit.
My Name: cineo

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Posts: 15
Joined: Thu Nov 21, 2013 12:01 pm
Model: C3 2002-2005, Original shape model
Year: 2003 (03)
Engine Size: 1.4
Fuel Type: Diesel
Mileage: 125000
Trim Level: VTR+
Gearbox: Manual 5 speed
DPF: No

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I respond to your questions
No I do not have a spare control unit
No I can not confirm that the control unit is healthy
I know how to remove the fan but I never did because it seems impossible
I know how to use a multimeter.

How can I tell if the control unit is faulty?

thx a lot!
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My Name: Arfur Dent

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Model: C3 2002-2005, Original shape model
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cineo wrote:How can I tell if the control unit is faulty?
Swap it over with one that you know works. Or try the suspect one in a car with a working heater fan.
You can add an avatar to your account - Avatar or change your vehicle details - Car Bio or even add a signature to your posts - Signature. But this is not all you can do in the User Control Panel :)
My Name: 927465

Contributor
Posts: 11
Joined: Mon Jan 13, 2014 7:06 pm
Model: C3 2002-2005, Original shape model
Year: 2003 (03)
Engine Size: 1.4 (8v)
Fuel Type: Diesel
Mileage: 110000
Trim Level: Desire
Gearbox: Manual 5 speed
DPF: No

Post

Speaking with other people I knew were defective panel but not him!
and then
No I do not have a spare control unit
Not sure if it is a language thing, but I assumed you had tried another control unit in your car and this hadn't worked either. Now I'm not sure what the situation is??

Can you confirm the situation?

You also never answered the question "Does the fan work on setting 4?"

I have a connection diagram that I can attach but I need to redraw it to make it easier to read(re drawing it will take time, and hence I only want to re draw it, if it will help you solve your problem)
My Name: cineo

Contributor
Posts: 15
Joined: Thu Nov 21, 2013 12:01 pm
Model: C3 2002-2005, Original shape model
Year: 2003 (03)
Engine Size: 1.4
Fuel Type: Diesel
Mileage: 125000
Trim Level: VTR+
Gearbox: Manual 5 speed
DPF: No

Post

No. I have not tried a new control unit.
No. The fun not working on setting 4
Yes, I tried a new control panel but the fan does not work.
i wait for your design.


forgive my english.
My Name: 927465

Contributor
Posts: 11
Joined: Mon Jan 13, 2014 7:06 pm
Model: C3 2002-2005, Original shape model
Year: 2003 (03)
Engine Size: 1.4 (8v)
Fuel Type: Diesel
Mileage: 110000
Trim Level: Desire
Gearbox: Manual 5 speed
DPF: No

Post

Hi Cineo,

I still don't know what you mean, so for clarity(as I think you might be naming items differently to me) I will put pictures with what I call them. I will try and use the names as I have them below for the rest of my posts.

What I call the temperature control unit:
temperature control unit.jpg
What I call the fan:
c3 fan.jpg
c3 fan.jpg (93.1 KiB) Viewed 219 times
What I call the resistor pack:
resistor pack.jpg
I will add the connection diagram on Monday. But it is a very simple circuit. 12V is connected to the fan, which is connected to the temperature control unit, which is connected to the resistor pack, which is connected to ground. On setting 4(of the temperature control unit) the resistor pack is not connected at all, it just connects directly to ground. On the other settings the temperature control unit connects small resistances in line with the fan to reduce the current and hence the amount of air blown.

I really want to help, but without understanding the scenario and what you have tried already, it is very hard to provide any useful advice.
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