Seat Leon - Only hot air at max 26?

sirwiggum

My fiancee has a 2010 Seat Leon 1.4.

If the heating temperature dial is set to 26 (maximum) and blows out lukewarm air, if it is set to any other value (even one notch back) it blows cold air.

The fact that it does heat at 26 would suggest to me that the heater matrix is functioning, it would seem that perhaps the rheostat used to control the values is only registering maximum or minimum values?

Anyone encountered anything like this, even on any other VW-group car?
Anyone any thoughts on what it could be?

BeenThroughItAll

If it has climate control or electronically controlled HVAC, it could well be one of the stepper motors controlling a mixing flap or blend motor.


Get it put on a VAG computer or on VCDS and that'll probably show up the fault.

sirwiggum

BeenThroughItAll wrote: »

If it has climate control or electronically controlled HVAC, it could well be one of the stepper motors controlling a mixing flap or blend motor.


Get it put on a VAG computer or on VCDS and that'll probably show up the fault.

Thanks.

It has basic dial-knobs, no climate control as such.

Would a fault show with an engine light?

It'll be taken back to the garage at some point

bryanb

Have heard of resistors that control fan speed blowing on Skoda. But I guess your fan is working on intermediate speeds?

sirwiggum

bryanb wrote: »

Have heard of resistors that control fan speed blowing on Skoda. But I guess your fan is working on intermediate speeds?

Yep the fan is working fine, blows low and blows high at various settings, the only issue is that it blows cold air unless the temperature dial is set to the highest point, which made me think of a rheostat which only functions with 0 or 1, the in between signal has gone.

I'm not even sure if it is a rheostat though, the dial does seem to have a 'click' at what should be temperature intervals.

TrickyWicky

sirwiggum wrote: »

My fiancee has a 2010 Seat Leon 1.4.

If the heating temperature dial is set to 26 (maximum) and blows out lukewarm air

The fact that it does heat at 26 would suggest to me that the heater matrix is functioning

Hang about it's only coming out with lukewarm air but you know it's at 26? - You do realise what you've written can be understood two ways don't you?

I'd doubt the heater matrix is at fault for a 4 year old car but you might have air in your coolant system that you should be venting though admittedly that doesn't explain why it works on full but not one mark less.

sirwiggum

TrickyWicky wrote: »

Hang about it's only coming out with lukewarm air but you know it's at 26? - You do realise what you've written can be understood two ways don't you?

I'd doubt the heater matrix is at fault for a 4 year old car but you might have air in your coolant system that you should be venting though admittedly that doesn't explain why it works on full but not one mark less.

26 as in the setting indicated on the dial.

Similar to this:



26 is shown as the highest setting.

I haven't put a thermometer to it, but it doesn't feel as hot as my Toyota would be at the highest temperature setting.

Any point before the indicated '26' and cold air is blown.

Ximian

Is the car at full operating temperature when you have turned the temp dial to 26 (ie. 90 on the temp gauge)?

Edit: TrickyWhicky asked the question which I had in mind, that the coolant system might have an issue.

sirwiggum

Ximian wrote: »

Is the car at full operating temperature when you have turned the temp dial to 26 (ie. 90 on the temp gauge)?

Yep the car, once warm after a few miles, is sitting 90 on the gauge, right in the middle.

Edit: Your edit re: the cooling system, this was my initial thought as the Celica had a coolant leak at one point, air was in the system and it was only blowing cold air.
Strange though that the Leon does blow warmish air at the 'max' setting.

Coolant level is between min and max.

Is there a coolant bleed on VW-group petrol (MPi I think) engines?

AdrianC

sirwiggum wrote: »

It has basic dial-knobs, no climate control as such.

The fact it has a rotary knob's not relevant. If it's marked with temp in degrees is - it's definitely thermostatic and electronic climate control, with stepper motors operating the flaps according to the interior temperature.

Would a fault show with an engine light?

No, but the climate ECU _might_ store fault codes, although you'd almost certainly need comprehensive diagnostics to get them, rather than a basic reader.

Get the engine up to temp, then test the temp of the radiator with your hand - it should be too hot (the water in it is going to be 80+deg) to touch, all over, evenly.

BeenThroughItAll

AdrianC wrote: »

The fact it has a rotary knob's not relevant. If it's marked with temp in degrees is - it's definitely thermostatic and electronic climate control, with stepper motors operating the flaps according to the interior temperature.



No, but the climate ECU _might_ store fault codes, although you'd almost certainly need comprehensive diagnostics to get them, rather than a basic reader.

Get the engine up to temp, then test the temp of the radiator with your hand - it should be too hot (the water in it is going to be 80+deg) to touch, all over, evenly.

Yep, VCDS or VAS will be able to read the climate ECU.