Clarification needed on Xantia Fan Speed Control and Temp

Post by **Rhothgar** » 20 Nov 2011, 21:40

I had problems with my fan speed around this time last year.

I cleaned the cabin temp sensor and lubed it up and things improved. Now, however, I have a nagging doubt about Automatic Climate Control operation and exactly how it should work.

With speed set to Auto, and temp to 22, I go for a run and everything warms up nicely. In fact, it seems too warm. So I switch onto Red (far right) and the fan speed decreases. Surely, it should speed up? If I slide it to 26, it speeds up.

If I leave it on 22, after a reasonable length of time, it seems to go really cool. I was wearing a thick fleece today and felt that, without it, I would have been chilly. 22 felt more like 18.

My Xantia has A/C also but this was off and presumably operates independently and causes no additional complications in diagnosis.

Does any of this point to the cabin temp sensor being faulty? And when I say fault, I'm really asking if the blue blob can somehow fail electronically.

Fan speed is fine on Max but move ONE click to the left (I believe there are 5 clicks to the stop position), the speed drops right off and it is not really audible but can be felt.

Also, what's the easiest way to gain access to Climate ECU please?

Thanks in anticipation.

Dommo · Post by **Dommo** » 21 Nov 2011, 02:35

I find the extremes of the temperature slider make the fans go slowly, one notch off full cold or hot seems to make the fans speed up.

I also have had an issue with temperatures.. The problem I found was the o-ring sealing the outside of the cabin air temperature sensor. The thing you cleaned up. Mine has torn before and this lets hot air from the head unit/behind the dash into the sensor so it thinks the cabin is much hotter than it actually is!

Post by **Rhothgar** » 21 Nov 2011, 08:31

I'd have never thought of that. That's an interesting response and it's certainly not too expensive to try.

I seem to recall the O-ring broke so I discarded it. The shroud to the sensor waggles fairly easy whereas I am sure it was firm before so perhaps I did discard.

Once you done this did it correct your issue?

Dommo · Post by **Dommo** » 22 Nov 2011, 22:23

It did yes, it's since happened again though because I fitted an o-ring off my S2 activa to my S1 VSX, and they're a different size so it's a tad overstretched, and has given up again. Really need to get it done again as it's very annoying, especially in the winter.

Post by **c.morewood** » 30 Nov 2011, 21:58

Where is the O ring/sensor located please?
I've noticed that with my heating at max and auto set, the fan speeds up and slows down perhaps 5 times in 10-15 seconds I wonder if this could be the o ring?
Thanks,
Chris

Post by **Rhothgar** » 30 Nov 2011, 22:22

Doubt that will be caused by an O-ring! Sounds like a faulty switch / contact. Have you read post on ignition switch modification? Not sure it will help you but it's an additional line to follow.

Post by **c.morewood** » 02 Dec 2011, 08:53

Thanks Rhothgar, but is't the mod only for Mk1's? I'm sure I read somewhere that the Mk2's already had the mod.

Clogzz · Post by **Clogzz** » 03 Dec 2011, 13:56

The Mk II has the modification, but even then the blower supply is still an area of problems.

There is also that the estate was made in a different factory to the hatchback, so the assembly was different.

Dommo · Post by **Dommo** » 04 Dec 2011, 19:50

c.morewood wrote:Where is the O ring/sensor located please?
I've noticed that with my heating at max and auto set, the fan speeds up and slows down perhaps 5 times in 10-15 seconds I wonder if this could be the o ring?
Thanks,
Chris

The only time my car has done that is when I had it running with the pollen filter and it's holder not fitted, it doesn't seem to like that!

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