C5 X7 weak aircon flow

[aranciata-oz]

You have not tested the full system. These ECUs monitor all their outputs and it will detect an error if they cannot see the appropriate load on the output. I suggest you leave the controller in the air box and stick your pin or a thicker piece of wire into the back of the white wire hole in the back of the connector and then monitor what is going on with the different fan speeds. That is how I measured the values in my car and you should be trying to replicate my method so you can compare the results.

Cheers, Ken

Thanks @Ken W - I guessed as much. Anyway, success ... with the controller connected I just got these figures an hour ago:

Ignition off - 0.01 volts (I forgot to flick the voltage selector to microns to get a more accurate voltage)
Ignition on - I think I missed this step
engine running with fan not running ie 0 segments - 0.01 volts
1 segment - 3.16 Volts
2 segments - 3.19 V
3 " - 4.25 V Fan still pretty quiet up to this setting
4 " - 5.29 V Registering air flow noise but not much
5 " - 6.22 V (No change in fan flow)
6 " - 7.38 V (No change in fan flow)
7 " - 8.69 V (No change in fan flow)
8 " - 11.66 V (No change in fan flow)

 

[aranciata-oz]

Thanks @Ken W - I guessed as much. Anyway, success ... with the controller connected I just got these figures an hour ago:

Ignition off - 0.01 volts (I forgot to flick the voltage selector to microns to get a more accurate voltage)
Ignition on - I think I missed this step
engine running with fan not running ie 0 segments - 0.01 volts
1 segment - 3.16 Volts
2 segments - 3.19 V
3 " - 4.25 V Fan still pretty quiet up to this setting
4 " - 5.29 V Registering air flow noise but not much
5 " - 6.22 V (No change in fan flow)
6 " - 7.38 V (No change in fan flow)
7 " - 8.69 V (No change in fan flow)
8 " - 11.66 V (No change in fan flow)

@Ken W and others - I'm guessing from the results of my tests, it appears the AC controller could well be operating without any issues, but rather the fan controller might be the culprit here, given the widespread history of its reliability (or lack there of!)?

If so, would Item #10 from this supplier be a safe bet?

Citroen

 

[Ken W]

Not sure which supplier you are considering for the 6441S7 part.

I would try a couple more tests before you order a part to make sure you are losing the volts within the fan speed controller. Plug you probe into the hole of the black wire on the connector and cycle up through the petals with the fan working. The voltage you measure should stay well below 1 volt. Then plug the probe into the back of the red wire at the opposite end of the connector and cycle the fan speed. That voltage should stay around 12 volts. I you get the readings as suggested, that will verify that the power feed and chassis return are operating normally.

Lastly plug your probe into the back of the red wire beside the white wire and cycle through the petals. This voltage should start up at 12 Volts and then decrease with each additional petal until it is down around 1 volts or so at maximum fan speed. If it comes down a bit and then does not reduce further with increasing number of petals, then that is a good indication that the fan controller is faulty.

Cheers, Ken

 

[Armidillo]

@Ken W and others - I'm guessing from the results of my tests, it appears the AC controller could well be operating without any issues, but rather the fan controller might be the culprit here, given the widespread history of its reliability (or lack there of!)?

If so, would Item #10 from this supplier be a safe bet?

Citroen

I don't think that's a supplier, so much as an online catalog. Although if you click on the part number you want, it leads to what looks like a supplier, but I haven't tried to order from them.

However now that you have the part number, getting one should be no problem. Eg. this mob are in Australia and should supply the real thing: https://runautoparts.com.au/topran-...F67M_vhhVgfr0kWg0aG1nANU6_PeaZZBoCcsIQAvD_BwE

Alternatively spareto.com gives you a huge range of manufacturers to choose from. You might even be able to find the original manufacturer's name on the part in your car, thus allowing you to be sure you are replacing like for like. Prices at Spareto look much cheaper, but beware the freight cost - they don't offer a cheap option!

https://spareto.com/products?utf8=%E2%9C%93&keywords=6441s7

 

[aranciata-oz]

Not sure which supplier you are considering for the 6441S7 part.

I would try a couple more tests before you order a part to make sure you are losing the volts within the fan speed controller. Plug you probe into the hole of the black wire on the connector and cycle up through the petals with the fan working. The voltage you measure should stay well below 1 volt. Then plug the probe into the back of the red wire at the opposite end of the connector and cycle the fan speed. That voltage should stay around 12 volts. I you get the readings as suggested, that will verify that the power feed and chassis return are operating normally.

Lastly plug your probe into the back of the red wire beside the white wire and cycle through the petals. This voltage should start up at 12 Volts and then decrease with each additional petal until it is down around 1 volts or so at maximum fan speed. If it comes down a bit and then does not reduce further with increasing number of petals, then that is a good indication that the fan controller is faulty.

Cheers, Ken

Great stuff @Ken W. I managed to do these tests just then, cycling up the petals:

- negative ground wire (actually yellow green for me) - at zero petal it 0.00V, then max'd out at 0.10V at petal #8.
- red wire - from petal #1 to #8 it was like 14.1V consistently
- wire beside the white wire (mine was actually black) - it started at 14.1v or thereabouts at petal #1, then as I cycled up it decreased to about 9.74V at petal #4 but stayed at that voltage all the way to petal #8 ... this is consistent with the airflow pattern I was getting.

So I suppose this confirms the voltage losses are within the fan controller? In the meantime, @Armidillo I'll look at the site you recommended ...

 

[aranciata-oz]

At long last …. WOOOOOHOOOOO! My aircon works at proper fan speeds again, thanks to Run Auto Parts replacing the Topran fan controller with the BEHR/Mahle one (they had sent me the Topran one the first time round but it just ran a constant speed …). Run Auto Parts has incredible service - they worked closely with me and when I explained to them it appears overwhelmingly (based on owner feedback worldwide) the non BEHR/Mahle controllers simply don’t work with the C5 X7, they immediately went about trying to source the BEHR for me - it took a while but I didn’t care! Can’t describe the joy I felt yesterday when switching on the AC shortly after installing the BEHR !

Thank you every single one of you here for all the help you’ve generously given - special mention to you @Ken W for taking the time to get me voltage readings from your own car and then walking me through the troubleshooting steps. And to @Armidillo for putting me on to Run Auto Parts - what a great mob!

Anyway two things out of this:

- the BEHR part is as per attached picture (cut out from the packaging) - just for everyone’s future reference.

- the Topran resistor that I have may well still work with another car make or model, and given Run Auto Parts kindly didn’t want me to return it, I’m happy to forward it to whoever wants it if they reckon it might work for their car (presumably non C5 X7!). Let me know …

 

[Tristesse]

AIRCON FAN ANNOYING LOW PITCHED NOISE 2015 MY X7 C5 Exclusive sedan 2.0L RHH engine

I've learnt a lot from this thread. Yesterday I heard a new noise in the air conditioning, a low pitched thrill in the fan system, more evident when I switched to recirculated air. It seemed to be coming from directly in front of me. I also got the impression the speed of that noise fluctuated for no good reason yesterday too. I could not find anything else wrong with the function of the system. I turned it down to 8 half leaves of fan speed and it almost disappeared. It was present all day. Maximum fan speed achievable and very noisy, perhaps like Ken W reports. Maximum temperature in Melbourne yesterday was 31 and the car had been parked in shade.

After reading this thread nothing much seemed to fit for an explanation, except perhaps that the fan controller module might be on the way out. I was not up to any of the clever things proposed here, except pulling out Fuse 11 from the engine bay upper fuse box. I did this and left it out for about a minute, scratched the blades a little with the key to little effect and it looked to have new scratches on it from me removing it. I put it back in and the car behaved perfectly for the rest of the day.

This morning I heard that noise again briefly, not as noisy as before perhaps, put the car forward and reverse a few times and it's been gone since. I washed the car only mildly dirty. I always clear the windscreen scuttle of any tree rubbish and there was very little there. I have made two half hour round trips to the local shopping strip including reverse parking twice there and when I returned. The aircon fan continues to function normally.

Is the apprarent effect of the fuse manoeuvre just a coincidence? Is there some baffle lubrication problem that I have righted by just mucking around?

I had an error message that put the car in limp home mode last week. Initial warning was faulty Parking brake. Next message transmission fault. I had pulled into the side of the road on a gentle upward slope to listen to something on the radio. Perhaps my manoeuvres were not as crisp as a machine might like of me, but I didn't do anything stupid. My mechanic was available immediately and wiped the error codes and all has been fine since. Could pulling the fuse have had the same effect on some rogue software thing with the fan controller? I gather these cars are never quite entirely 'off' when switched off.

 

[Ken W]

Some leaves always get through the slotted barrier near the wiper pivots and as the interior fan in the system is before the pollen filter, the leaves can find their way into the fan blades. I have heard some real buzzers over my 15 years of ovnership, but they go away with time as the leaf wears away or decays or comes out when the pollen filter is changed.

You are lucky it is so cool down there.

Cheers, Ken

 

[Tristesse]

Thanks very much Ken. That makes best sense, something mechanical. I've ground it away. Maybe the creation of a moist environment helped.

It is now 37˚C today, but 22˚ for the rest of the week. I washed both cars this morning. My wife's 2009 407 is only two or three years overdue for service but it was filthy, the wiper pivot wells always full of leaves and the car regularly filthy, parked in the street. But nothing ever goes wrong with it. Now it's clean she might agree to book it in for service.

Keep cool.

Richard G

 

[aranciata-oz]

AIRCON FAN ANNOYING LOW PITCHED NOISE 2015 MY X7 C5 Exclusive sedan 2.0L RHH engine

I've learnt a lot from this thread. Yesterday I heard a new noise in the air conditioning, a low pitched thrill in the fan system, more evident when I switched to recirculated air. It seemed to be coming from directly in front of me. I also got the impression the speed of that noise fluctuated for no good reason yesterday too. I could not find anything else wrong with the function of the system. I turned it down to 8 half leaves of fan speed and it almost disappeared. It was present all day. Maximum fan speed achievable and very noisy, perhaps like Ken W reports. Maximum temperature in Melbourne yesterday was 31 and the car had been parked in shade.

After reading this thread nothing much seemed to fit for an explanation, except perhaps that the fan controller module might be on the way out. I was not up to any of the clever things proposed here, except pulling out Fuse 11 from the engine bay upper fuse box. I did this and left it out for about a minute, scratched the blades a little with the key to little effect and it looked to have new scratches on it from me removing it. I put it back in and the car behaved perfectly for the rest of the day.

This morning I heard that noise again briefly, not as noisy as before perhaps, put the car forward and reverse a few times and it's been gone since. I washed the car only mildly dirty. I always clear the windscreen scuttle of any tree rubbish and there was very little there. I have made two half hour round trips to the local shopping strip including reverse parking twice there and when I returned. The aircon fan continues to function normally.

Is the apprarent effect of the fuse manoeuvre just a coincidence? Is there some baffle lubrication problem that I have righted by just mucking around?

I had an error message that put the car in limp home mode last week. Initial warning was faulty Parking brake. Next message transmission fault. I had pulled into the side of the road on a gentle upward slope to listen to something on the radio. Perhaps my manoeuvres were not as crisp as a machine might like of me, but I didn't do anything stupid. My mechanic was available immediately and wiped the error codes and all has been fine since. Could pulling the fuse have had the same effect on some rogue software thing with the fan controller? I gather these cars are never quite entirely 'off' when switched off.

@Tristesse I just encountered this same low pitch noise today - a lot worse when aircon is at 8 petals max. Ah this sh** of a aircon system is driving me nuts. I’m going to try what @Ken W suggested and look for some leaves as part of my pollen filter clean.

 

[fritzelhund]

You cannot swear at a good GERMAN made air con !!!!

 

[309B6D]

Trestesse, Somewhere in this thread I read that when using Reverse the AC is switched to Recycle mode (to avoid sucking in diesel exhaust fumes)
When Drive is selected the AC switches back to its previous setting.

You said your noise came back again after reversing in the car park.
The noise went away after repeated reverse/forward moves.

Maybe the closed circuit is not releasing something properly when you start going forward again. A restricted flow might cause extra noise from the fan.
Is a flap not returning fully? Multiple uses are freeing it and letting it return properly?