Citroen S1 Hot and Cold Slider Switch Problem

citronut · Post by **citronut** » 13 Dec 2010, 09:06

thats the one

regards malcolm

Post by **Rhothgar** » 17 Dec 2010, 10:43

Hi Malcolm

Quick one!

Start to finish, if I had the parts to hand, would it take approx. to do this job?

Post by **CitroJim** » 17 Dec 2010, 10:56

Rog,

That's not the normal failure mode for the blower regulator. Normally the transistors fail short-circuit and the blower runs uncontrollably at top speed whatever the slider is set to. Personally, this is the only fault I've seen on it so changing the transistors on-spec as it were may be a waste of time. The only thing I will say is that on top speed a relay operates to deliberately short out the transistors so if the blower runs only on max and is stopped dead in all other positions then the regulator may be faulty.

To confirm this, check the input conditions to it. This thread will help.

Post by **Rhothgar** » 17 Dec 2010, 11:17

Hi CitroJim

Thanks for your input.

Blower operates on MAX speed and Auto but if slider is 5 - 10 mm left of MAX then speed reduces down considerably but it is definitely still blowing - a little more than gently if that helps.

What does the ignition switch mod do exactly?

I have very limited time to do any heating work related stuff as we are driving to Austria in sub-zero conditions next week and I don't want to die under a travel blanket if we get stuck.

Getting the winter tyres fitted this afternoon and could with getting my head straight on what else I need to do.

The other thing I may have mentioned is that temperature is fine on Red (Max) and fine on Cold (Blue) but in between is not really controllable.

I tried blowing out temp sensor and no improvement. Any tips for this too? I spoke with Citroen and they want £50 for the cabin temp sensor but I could ill-afford to buy that and it not be that causing the problem.

Post by **CitroJim** » 17 Dec 2010, 11:46

All the ignition switch mod does is to bypass high-resistance contacts that stop the blower blowing under any circumstance. This won't be your problem.

Have you peeked down the cabin temperate sensor with a torch to make sure the little fan is actually spinning? It can seize on its shaft and stop.

That is not the only temperature sensor. There's one is the cold air intake, one in the middle of the heater box and a further one low-down on the footwell vents.

Any could be duff. All but the cabin sensor and the footwell sensor are very hard to get to and the only way to check their operation easily is with a Lexia diagnostic session.

If you get good warm air out of the vents with the slider hard over on the red section then it would appear there's a problem with the sensors or the climate ECU.

Does it start off nice and warm when set to say, 22 degrees for the first few miles and then cool right off? This is a good pointer to a sensor being at the root of the problem. This happens when one or more sensors detect (falsely) that the cabin is plenty hot enough...

Clogzz · Post by **Clogzz** » 17 Dec 2010, 13:55

This looks like a touchy speed slider, topic here:
http://www.frenchcarforum.co.uk/forum/v ... hp?t=23767

Post by **Rhothgar** » 17 Dec 2010, 14:55

CitroJim wrote:Have you peeked down the cabin temperate sensor with a torch to make sure the little fan is actually spinning? It can seize on its shaft and stop.

No but I will do!

CitroJim wrote:That is not the only temperature sensor. There's one is the cold air intake, one in the middle of the heater box and a further one low-down on the footwell vents.

I am aware of this as I recently subscribed to the Citroen Service site. Very useful! Part no. 6445 L5 from memory?

CitroJim wrote:Any could be duff. All but the cabin sensor and the footwell sensor are very hard to get to and the only way to check their operation easily is with a Lexia diagnostic session.

Is this a Citroen specific diagnostic system?

CitroJim wrote:If you get good warm air out of the vents with the slider hard over on the red section then it would appear there's a problem with the sensors or the climate ECU.

Does it start off nice and warm when set to say, 22 degrees for the first few miles and then cool right off? This is a good pointer to a sensor being at the root of the problem. This happens when one or more sensors detect (falsely) that the cabin is plenty hot enough...

I will test this this afternoon as the engine is now hot. It will have cooled a little by the time I get back into it.

Thank you for all your advice so far.

Post by **CitroJim** » 17 Dec 2010, 16:07

Yes, the Lexia is the Citroen specific diagnostic tool and if used will be able to look at 'live' parameters from the climate ECU and more specifically what temperatures the sensors are seeing and what they believe the temperature of the air exiting the vents to be.

It'll also tell you the believed cabin temperature, test the blower and operation of the motorised flap that controls temperature.

A number of members have a Lexia and their details can be found here.

Not only that. it'll also tell you if the water temperature is correct electronically. It's just struck me that the heater electronics are more or less disabled if the engine is cold; the blower runs at speed only if the engine is up to reasonable temperature. Having said that I believe this is not so when the heater is set to full demist mode.

In fact, that's a useful test. On Auto, does the blower speed up when the heater is set to full demist and then slow down again on any otehr position?

Post by **Rhothgar** » 17 Dec 2010, 18:59

I spoke to my mate, Marmite, about the Lexia and he has some diagnostic kit which can do this.

He believes, if memory servers him correctly, that the connector is a 12 pin as opposed to the normal 16 pin. Is this correct?

Also, where is the ODBC or diagnostic socket on a '96 Xantia. I'm sure we couldn't find one when we looked previously. Certainly nothing for the engine because it's a proper diesel!

That damned car. I drove up to my mate's garage to get the winter tyres fitted and the temperature seemed to be right so now I think it is an intermittent fault.

The blower is blowing quicker than it does when I am experiencing problems in the same position i.e. 10mm left of max.

I played around with the temperature and it seems to cool quicker down to the BLUE preset than when I put it back upto Midway 22 degrees - it tends to take longer to heat back up. Then it seems to over-compensate and cool down again.

When I put the fan control speed to MAX, the problems seem to start. It seems and I do not know if this will be the same every time, that if I put it up to MAX and then slide it back down to left of max that it slows down a lot more when the engine temp is getting up to its normal range.

I think this Lexia will probably give us the answer we're looking for.

Are there any pointers on what is normal on the Lexia readouts?

Post by **CitroJim** » 17 Dec 2010, 20:22

ODBC Socket?? You must be in the same business as me

(ODBC aka Open DataBase Connector) I spend a lot of my working day in the company of MSSQL

Pays the bills...

The MK1 Xantias have a totally unique (to PSA vehicles) 30 pin diagnostic socket under the lid of the cabin fusebox down by your right knee.

Sadly it's not OBD-II (or even ODBC) compliant and is proprietary to Citroen and can only be read using a Lexia, ELIT or Proxia diagnostic machine. The only third-party one I'm aware of that will read it is the Sykes-Pickavant ACR-4. Hopefully Marmite has one of these?

Even MK2 Xantias are not ODB-II compliant even though they have an OBD-II style 16 pin socket.

I'll be more than happy to hook my Lexia up to Old V6 next time it's all nice and toasty warm to get some typical readings for you...

Post by **Rhothgar** » 18 Dec 2010, 09:34

CitroJim wrote:ODBC Socket?? You must be in the same business as me (ODBC aka Open DataBase Connector) I spend a lot of my working day in the company of MSSQL

No. I'm not as clever as you if you understand Squirrel. I can't even get my head around Access - wish I could I have some database issues which I don't understand.

Marmite has a Lexia and a Proxia and even a member of staff with an ACR-4 (which may be at home) but he has them. Problem for him, and therefore me, is that the screen on his Lexia is kaput and he is not sure what serial connector his 30 pin has off the top of his head.

I told him I can probably sort either his laptop screen out or clone the disk and provide a laptop to get that up and running.

I have a Snap-On MT2500 would this be of any use with the right key and connector?

The Primary Cartridge states Makes:All so I feel sure sure Citroen sit within that cartridge though not sure.

I am going to scan Ebay quickly and see if anyway local to me has any Snap-On keys and connectors for this MT2500 scanner.

Still need to shine my torch down the sensor though. Mental note to do that later.

Post by **CitroJim** » 18 Dec 2010, 10:06

I don't understand Access either

Shame Marmite's Lexia is broke. There's no way of putting an external monitor on it sadly... So often the problem in a Lexia is simple. The DIMM often develops bad contacts. A good test of basic function is if it gives two rapid bleeps on switch-on. If not, check the DIMM.

Unfortunately, cloning the disk and trying to boot it on a laptop won't work. Even if you could, the real magic is the interface board and that's not on any standard ISA slot.

Not sure at all about the Snap-On machine.

The quickest method if you cannot get the Lexia up and running or find anyone local with one is to bite the bullet and buy a Lexia 3 Chinese Copy on eBay.

Meantime, I'll fire mine up and get some typical readings for you...

Post by **Rhothgar** » 18 Dec 2010, 10:16

Brilliant!

Thanks Jim.

He does say his screen his dead. So basically I've give it a boot, so to speak, when I get there and if no post beep then check DIMM and clean with spirit or pencil eraser!

I would have thought screen would still boot though and show something. I know he was, rightly, moaning that one of his staff had broke it and just put it aside so maybe it's physical damage - not sure.

Post by **CitroJim** » 18 Dec 2010, 10:20

It's a funny quirk of the Lexia that if the DIMM is out the screen will remain completely blank.. It was the original fault with mine...

On the two bleeps, the screen will flash briefly "System Test" and then go blank again whilst it boots.

Post by **CitroJim** » 18 Dec 2010, 11:30

Rog,

Below is a screenshot taken from the Lexia after a nice run with the cabin nice and toasty...

The meaning of each parameter is thus:

Temp. Selected: As set on the slider.

Ambient Temp: The reading given by the sensor in the air intake. The real ambient was -3 but the air is warmed a tad by the engine bay.

Int. Temp: That read by the cabin sensor (the one in the dash behind the fan).

Evap. temp: The temperature of the Aircon Evaporator.

Blown Air vent: The temperature of the air in the face level vent duct (effectively middle of the heater box just after the matrix.

Blown Air Footwell: As above but in the footwell vent duct.

Blower Mode: AUTO if the blower switch is set to auto mode.

Note that the duct temperatures are very high as these are sensed in the heater box where things are very toasty indeed. the air soon cools on exit from the vents.

The cabin temperature was low as the drivers door was open a crack to allow the diagnostics lead to run outside the car.

Hope that helps...