C bloody 5 again

Hiya all, this time it's the heater farting arsing about. The temperature display on the top screen, where the MPG figures are, shows a temp of 35-45, it varies, so the climate control thinks its really hot outside, so even when i set 27 on the heat controls it blows cold air, that is untill i set

28 on the dials, then it goes into Roasting Mode. So, has anyone any ideas on this one please. Also, when it rains & i switch the wipers on, either auto or standard wipe, The drivers window comes down about 4". When i close the window, it goes up stops then returns to the 4" open place. Any ideas ? Or is it time to buy a Xsara estate ? Cheers. Ray
Reply to
olddog
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"olddog" haute in die Tasten:

I have made similar experiences with my `94 Xantia VSX. The car has an automatic temperature control, which means that you choose the desired interior temperature with a switch (between 17°C and 27°C), the french electrobox does the rest, adjusting heating temperature and fan speed. If it is warmer outsides than you want to have it insides, you can switch on the Air condition with an additional switch. So far so good.

I have found out that this system works better when it is sunny and hot outsides than on cold, wet, dark days. During winter I found that the heating system produced warm air after just half a mile of driving, but very often it stops heating when there are 18°C inside te car - very unpleasant.

I was able to track down one fault: There is a temperature sensor built inside the dashboard, just near the clock. This sensor is about the size of a cigarette lighter, and it has a small electric motor and a fan. This fan is bound to produce a constant airflow around the temperature sensor itself (the sensor seems to be a temperature regulated resistor). The whole sensor unit has four wires, two grey wires, one black, one red. I assume that two wires power the small fan, while the other two wires connect the sensor to the heating system. I have found out, that this fan does not work most of the time. If I drive the car 30 days, the fan may run on one or two days. I have also found out that the whole unit gets warm when the fan does not run. Maybe something is blocking the fan (although I have not found any sign for that).

If the fan does not transport fresh air to the sensor and if the sensor unit gets warm, the sensor will probably read a false, too high temperature - and it will switch off the heating:-(

I have found out some kind of strange workaround. I have pulled the sensor out of the dashboard and fixed it to one of the vent air nozzles (the right one of the two central nozzles just above the radio). Now I can force the ventilation of the sensor by simply open or close the nozzle. This does affect directly the ability of the system to regulate itself by itself, so it requires some manual regulations. Up to now this workaround works quite well, I was able to maintain a sufficient temperature in the car. I don't know how this will work in the winter time.

Why didn't I just change the sensor? First of all, I am lazy and greedy. These sensors are for sure handmade by a bunch of aerospatiale engineers in their spare time between two Ariane rocket launches, so they will cost a fortune. Besides that I cannot reach the wiring plugs without taking apart the whole dashboard - I'd like to avoid that. Second reason: I am not entirely sure, wether the faulty sensor is the only reason for the errative heating. If I were, I'd be more enthusiastic about getting the sensor done.

I have heard about problems with this sensor and the fan in Xantia and XM. Maybe this can be helpful for the C5 also.

Frank

Reply to
Frank Kemper

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Makes me glad that my ZX has a lever to adjust the heat from the heater, and handles to open the windows. Why do "they" have to complicate things?

Reply to
Whiskers

Whiskers haute in die Tasten:

Answer No. 1: A flawlessly working temperature and climate control is a dream. It is one of the most pleasant convenience features which come to my mind when I think about modern cars.

Answer No. 2: "They" have to complicate things, because in between shooting dozens ariane rocket into space, the engineers get bored and look for a real challenge;-)

Frank

Reply to
Frank Kemper

So boring though; and how do you know the weather is changing outside if you are insulated in your air-conditioned box?

Hmm. I'd rather they tried to improve wind-screen wipers and work out how to stop glare from a low sun reflecting off the not-quite-black-enough trim inside the windscreen. Self-repairing bodywork would be useful too :))

Reply to
Whiskers

Whiskers haute in die Tasten:

Answer No. 1: I don't care;-) Answer No. 2: A terrific digital display informs me about the temperature outsides;-) Answer No. 3: My other car is a convertible, in case I want to feel the weather;-)

Frank

Reply to
Frank Kemper

Reply to
olddog

Hi!

I guess that outside temp. sensor is faulty or has some contact problems. It is located under co-driver's mirror. Been there, done that...

cheers, make

Reply to
Markku Suominen

Thank you, thats just the info i needed. Cheers. Ray

Reply to
olddog

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