Citroen C5 X7 mk3 climate control heater fan fault

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Y Cymro
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Citroen C5 X7 mk3 climate control heater fan fault

Post by Y Cymro »

The heater for on my C5 is stuck on a medium fast setting however I adjust the temperature control when in automatic mode. When set to manual, setting the fan speed control to off stops it, but whichever fan speed is chosen it always turns at a medium fast speed.
From other posts here it seems the heater resistor is a common fault so I bought a non-branded one from eBay for £19 and fitted it thanks to Marc’s guidance in another post.
The new one turns the fan at a medium speed (ie slower than the original one) and adjusting the temperature controls speeds or slows the fan slightly, but it never blows fast nor switches off. I cannot turn it off manually either.
The seller has sent me a replacement but it’s exactly the same. Because the fan speed of the replacement is different to the original, and because I can turn off the fan using the original resistor I assume the problem is with the resistor rather than the fan, and that my new replacements don’t work with my car.
I’m tempted to buy a Bosch branded one for about £40 but am wary of throwing more money at it as the cheap replacement resistor didn’t work (though it produced a different fan speed to the original one). I’ve completed a BSI reset after replacing the part.
I’d appreciate your thoughts.

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GiveMeABreak
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Re: Citroen C5 X7 mk3 climate control heater fan fault

Post by GiveMeABreak »

The cheaper aftermarket ones are notorious for failing - they are often not up to the job. Try and get a Valeo branded one.

I don't have your VIN to hand, but if you pop that up I can probably point you to one.

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Re: Citroen C5 X7 mk3 climate control heater fan fault

Post by Y Cymro »

Thanks Marc

VF7**************[VIN obfuscated, can be read by forum staff]

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Re: Citroen C5 X7 mk3 climate control heater fan fault

Post by Y Cymro »

In fact I can’t find a Bosch branded on, only a Behr-Hella at around £40. The part number is 6441S7 which I assume is right as it’s the same number on the two Chinese ones which fit but don’t work.
Any idea where I can find a Valeo one for around the same price? Have done a Google search but nothing popped up.

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GiveMeABreak
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Re: Citroen C5 X7 mk3 climate control heater fan fault

Post by GiveMeABreak »

Ok, so the part is 6441S7. I meant Hella / Behr - not Valeo, but in any case Citroen main dealers sell these for £150.35 inc. VAT. I have found several about the £90 ish mark that are genuine ones:

https://www.ebay.co.uk/itm/GENUINE-CITR ... SwymxVMmsz

A Hella one here for Just under £40:

https://www.ebay.co.uk/itm/Hella-AIR-CO ... SwzzZZfdT1

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Re: Citroen C5 X7 mk3 climate control heater fan fault

Post by crapday69 »

or you could try a scrap car that has a working fan.

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Paul-R
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Re: Citroen C5 X7 mk3 climate control heater fan fault

Post by Paul-R »

In my experience the heater blower either works correctly or not at all so there might be a fault with motor that stops it going any faster (implying that the control unit is working correctly) or that, as has already been said, the control units are misbehaving.

It does seem strange that all control units are giving the same result so I would suggest trying the shorting loop trick to see if the motor will run at full speed without the control unit in circuit. If it does run at full speed then try putting the original control unit back in just to see if everything now works correctly. None of this may happen of course but it will limit what could be wrong.

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Re: Citroen C5 X7 mk3 climate control heater fan fault

Post by Y Cymro »

Hi Paul
Yes. with the original OEM control unit fitted the fan always runs at a high speed (though not the fastest speed) and I can use the manual control on the dashboard (ie not Auto) to stop the fan running. On both eBay replacements the fan always turns at a medium speed and won’t turn off using the control set to manual.
I’ll bridge the terminals but I think this will work as expected.

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Re: Citroen C5 X7 mk3 climate control heater fan fault

Post by crapday69 »

my fan runs at top speed for a second as I start the car, then goes to the slowest setting. I have tried 2 different modules and still the same. I can live with this slow speed, it just take a little longer to de-mist the windscreen and heat the car.

Gary.

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Re: Citroen C5 X7 mk3 climate control heater fan fault

Post by Paul-R »

Y Cymro wrote:
17 Apr 2019, 16:49
... I can use the manual control on the dashboard (ie not Auto) to stop the fan running.
Now that is interesting. If you can actually get most of the speeds (albeit not full speed) then that suggests to me that the control unit isn't being sent the correct instructions by the climate control ECU. Maybe one of the many sensors that provides data to the ECU isn't doing its job and the ECU can't make a valid decision as a result.

I'd still like to know whether the fan can blow at full speed with a shunt in place. And then see what happens when the control unit is put back in circuit.

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Re: Citroen C5 X7 mk3 climate control heater fan fault

Post by Paul-R »

crapday69 wrote:
17 Apr 2019, 16:53
my fan runs at top speed for a second as I start the car, then goes to the slowest setting. I have tried 2 different modules and still the same. I can live with this slow speed, it just take a little longer to de-mist the windscreen and heat the car.
What happens if you press the defrost button? What happens if you select the fan speed manually?

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Re: Citroen C5 X7 mk3 climate control heater fan fault

Post by Y Cymro »

Paul-R wrote:
17 Apr 2019, 18:33
Y Cymro wrote:
17 Apr 2019, 16:49
... I can use the manual control on the dashboard (ie not Auto) to stop the fan running.
Now that is interesting. If you can actually get most of the speeds (albeit not full speed) then that suggests to me that the control unit isn't being sent the correct instructions by the climate control ECU. Maybe one of the many sensors that provides data to the ECU isn't doing its job and the ECU can't make a valid decision as a result.


Can’t get most speeds, on the OEM unit I get quite fast or off, on both eBay replacements I get medium speed only. I can’t alter the speed on any of the units.

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Re: Citroen C5 X7 mk3 climate control heater fan fault

Post by Paul-R »

Ah, that's slightly different. OK, just waiting to see what speed the motor runs at with the shunt in position.

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Re: Citroen C5 X7 mk3 climate control heater fan fault

Post by Y Cymro »

So pull the connector off the control unit and bridge the two heavy cables in the connector?

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Re: Citroen C5 X7 mk3 climate control heater fan fault

Post by crapday69 »

Paul-R wrote:
17 Apr 2019, 18:35
crapday69 wrote:
17 Apr 2019, 16:53
my fan runs at top speed for a second as I start the car, then goes to the slowest setting. I have tried 2 different modules and still the same. I can live with this slow speed, it just take a little longer to de-mist the windscreen and heat the car.
What happens if you press the defrost button? What happens if you select the fan speed manually?



If I hit the defrost button or try and change the speed manually it just stays the same. The only time the fan runs faster is for that second on startup, then it goes to a low setting. Think I would put it in to get sorted if we had really bad winters, but the car still heats up hot in about 5/6 minutes.