Hi

I don't think this issue has been posted after having searched, but forgive me if the same question has been asked and I haven't seen it.

 

The temperature dial on my 2012 Superb tends to get very hot, when turned to maximum - but when turning the dial one mark down from maximum, it blows 'luke warm.'

 

There doesn't seem to be a discernible 'degree' decrease  in temperature when adjusting it down a degree. Hence it is either very hot, or luke warm. 

 

Has anyone got similar issues or an idea on how to correct this?

 

Many thanks

I think you needs to test this over a range of ambient temps.

for example, if the cabin is around 24c and you set to max, you will get hot air, if you drop the requested temp to 23 you will only get luke warm as the cabin has reached the temp asked for.

the same as if you requested 17 and the cabin is 24 you will get cold.

perhaps test again but note the cabin temp with a separate thermometer?

On 17/01/2020 at 14:53, Ospreys said:

Hi

I don't think this issue has been posted after having searched, but forgive me if the same question has been asked and I haven't seen it.

 

The temperature dial on my 2012 Superb tends to get very hot, when turned to maximum - but when turning the dial one mark down from maximum, it blows 'luke warm.'

 

There doesn't seem to be a discernible 'degree' decrease  in temperature when adjusting it down a degree. Hence it is either very hot, or luke warm. 

 

Has anyone got similar issues or an idea on how to correct this?

 

Many thanks

 Did you ever solve this?  I have the same issue.

 

On a cold day (air temp below 10 degrees) it will only blow hot air on maximum - on anything else it's blowing lukewarm / cool air.

Some possibilities.

1) Sensor or servo failure, you'll need a VAS or VCDS scan to identify.

2) Re-calibrate flaps for climatronic: hold down face-vent and AC button until the lights flash alternately.  This will re-learn the flap servo end stops.  You might not have climatronic so not sure if this is applicable to you.

3) Thermostat failure.  When the heat knob is at full, it enables the electric booster heater (if fitted).  When not at full, the heater is enabled under certain conditions but not others.  This scenario would be evident if your water temperature gauge doesn't reach the middle 90degreesC position after driving for some time.  A common one is that the gearbox cooler thermostat (DSG) fails open, so the water never really warms up unless the engine is working hard.  The part is cheap and easy to swap.  Disregard if you have a manual gearbox.  Search this forum for DSG thermostat, some nice people have written good guides.

4) The system never really blows really hot or really cold unless the setting at the endpoint.  It's designed to mix the air to avoid extremes. Drivers transitioning from Japanese cars (we had a Toyota that would freeze your legs the aircon was so cold) to these cars tend to think that if the air is not hot or cold then it's not really working.  That's what superbdreams is pointing out above.  The hottest setting on the dial is 'max heat' and just heats as much as possible and doesn't control the temperature.

5) I had one where the wiring to the inside/outside air servo failed so it was stuck on recirculate.  The servo was fine, it was the wiring that failed (no idea why, it's never been touched).  This was evident as VCDS reported that the servo signal was implausible.  Not the same as your issue, my problem was the car windows would fog up in the cold as it wouldn't select outside air.  But the wiring can fail unexpectedly.

12 hours ago, wokwon said:

Some possibilities.

1) Sensor or servo failure, you'll need a VAS or VCDS scan to identify.

2) Re-calibrate flaps for climatronic: hold down face-vent and AC button until the lights flash alternately.  This will re-learn the flap servo end stops.  You might not have climatronic so not sure if this is applicable to you.

3) Thermostat failure.  When the heat knob is at full, it enables the electric booster heater (if fitted).  When not at full, the heater is enabled under certain conditions but not others.  This scenario would be evident if your water temperature gauge doesn't reach the middle 90degreesC position after driving for some time.  A common one is that the gearbox cooler thermostat (DSG) fails open, so the water never really warms up unless the engine is working hard.  The part is cheap and easy to swap.  Disregard if you have a manual gearbox.  Search this forum for DSG thermostat, some nice people have written good guides.

4) The system never really blows really hot or really cold unless the setting at the endpoint.  It's designed to mix the air to avoid extremes. Drivers transitioning from Japanese cars (we had a Toyota that would freeze your legs the aircon was so cold) to these cars tend to think that if the air is not hot or cold then it's not really working.  That's what superbdreams is pointing out above.  The hottest setting on the dial is 'max heat' and just heats as much as possible and doesn't control the temperature.

5) I had one where the wiring to the inside/outside air servo failed so it was stuck on recirculate.  The servo was fine, it was the wiring that failed (no idea why, it's never been touched).  This was evident as VCDS reported that the servo signal was implausible.  Not the same as your issue, my problem was the car windows would fog up in the cold as it wouldn't select outside air.  But the wiring can fail unexpectedly.

 

Thanks Wokwon, much appreciated.

1) - I think this needs to be my next port of call

2)  I've recalibrated the climatronic and will go for a drive this evening to see if that's improved things.

3)  I'm in the UK so I don't think my (manual) car has the electric booster.  If it did I'd expect fairly much instant heat from when the car is turned on, which I don't get

4)  I've also come from Japanese cars, but last winter I was driving about in UK winter temperatures and the only way to get the car warm was to run the heating on max, otherwise cool air just got blown so I think the car genuinely has an issue.

5)  When I turn recirculate on an off I can hear things moving and the noise changes significantly, so I don't think that's the cause.

 

Have you ever heard of defective / broken cabin temperature sensors?  I'm sure I saw a post about this on this site a few months ago but I cannot find it.

 

Thanks ever so much for your help.

 

16 hours ago, flickyspinny said:

 

 

Have you ever heard of defective / broken cabin temperature sensors?  I'm sure I saw a post about this on this site a few months ago but I cannot find it.

 

Thanks ever so much for your help.

 

 

Not directly heard of but no reason why it would be impossible to fail.   Most of them are just basic thermistors.

 

The cabin temperature sensor is behind the small 5mm-ish glossy circle in the clima control panel.  It's possible to put the clima in diagnostic mode where the controls can select values to be read out on the media screen.  I don't have a channel map for the Superb 2, only for the old A5 VWs.  This would enable you to display a direct read-out of the cabin temp sensor (and other sensors).

 

There are additional sensors in the intake plenum, and in each outlet (left centre and right high outlets, winscreen and left and right footwell outlets).  There are two outside air sensors, one just behind the front bumper (don't think this one is used for clima, think it's for engine only) and one in the intake plenum (often combined with an pollution sensor).  There is also a sunlight sensor just aft of the windscreen defrost vent outlet that can measure sunlight intensity to the left and right sides.  These are all considered when selecting the airflow and heating/cooling settings so a failure of any could cause odd things to happen.  VAS/VCDS would probably make the failure obvious.

Thank you ever so much Wokwon.  That's probably the most comprehensive response I've ever received to anything on the internet.  I'm currently liaising with a very generous local briskoda member who has VCDS to get a scan and will work from there.  I'll keep this thread updated as I make progress.

 

Update - issue seems to be confined to drivers side... the passenger side is working fine.

 

OK, so a very generous local member has scanned my car for me and I have the following fault:

9473138 - Motor for Left Temperature Flap

B108C 54 [009] - Missing Calibration / Basic Setting

 

Seems weird that I believe this is located in the passenger footwell (RHD) to control the drivers heat, but looks like that's what I'm going to go with for the moment.

 

Will keep this updated.

Finally got around to looking further at this, and courtesy of this I decided to check out the temperature sensor on the drivers side.  The video below shows roughly what the temperature sensors look like.  Of course, on the Skoda they're an actual PITA to access (particularly the left hand side) so I couldn't swap them over to test them.

https://www.vwvortex.com/threads/right-temperature-flap-fault-code.9458984/

 

However, I did get check the resistivity and got a reading back of 1345 ohms.  Based on the video above, that seems very low, which might mean that the sensor is reading a very high temperature which means that the heating doesn't do anything on the drivers side unless I ask it for full heat.

 

Replacement sensor ordered, hopefully that'll solve the issue.  If it does, I suspect that the error reported above about the error for the left temperature flap could be completely unrelated.

 

The replacement sensor arrived today.  Don't know if it's worked yet because it's too warm to check.

 

Anyway, a few photos on where the sensor is and how to access it.

 

If you remove the fusebox cover from the drivers side, you can see the sensor tucked away in the dark space above the silver bracket.  Photo of general area and close-up here:

 

 

To get access to the area, open the cubby-hole by the driver's right knee.  Using a screwdriver gently lever it so that it opens out completely.  This gives you access to 4 torx screws that need to be undone to remove the whole assembly.  There is one larger torx screw underneath the dash (not pictured) that also needs to be removed.  It's pretty obvious which one, once you've undone the other four.

 

 

Now you can look up and see the sensor.  Simply turn it 90 degrees and it will drop out.  Disconnect the connector, put the new one on, and replace it.  Refitting is a reversal of dismantling.

 

Next picture is of the cross-shaped hole where the sensor would sit.  Photo after is the sensor in position.

 

 

I really hope this works...

 

Edited 26 June, 20214 yr by flickyspinny

And to update, yes it did work.

Hi Flickyspinny

ive got an issue with my car.

Something happened and the heater started blowing cold ( thought wife had altered it) 

More into the journey I realised that something was wrong.

I reset the flaps before making return trip 

Temp set at 22 but blowing cold misting screen up, turn up slightly (24) and it was blowing red hot ( fan on two).

Then next day playing about with it noticed drivers side blowing cold but passenger warm.

Does this sound like a sensor fault you had 

Need to see guy at work to scan it 

Any help appreciated 

cheers

 

 

 

Edited 1 October, 20223 yr by Snapper1725

I have the same problem on the passenger side - blowing cold air. Where is the temperature sensor on the passenger side and does anyone have any video tutorials on how to remove it ?