Heater controls, should this be happening

[Number 6]

I recently posted about a problem with my AC controls.
This is what happens.

Turn on and start the engine, Turn on the heater controls, The display shows the following.

Temp both sides. Econ and Auto light up, the green light for recirculation comes on.
And the fan is running
NO display for which vents are open.

To get the Auto light out you need to switch the Green recirculation switch off.

To see which vents are open you need to press the appropriate button.



You then have a normal working Econ system
Doing any other sequence will not work.


When you stop the car, go back to it and start it up again you have to go thru the same procedure

Anyone any ideas??


PS, I have tried a Battery off reset,, No difference.

[macafee2]

I cant help but how do you know which vent is open and how do you open and close it?

macafee2

[jackatesme]

Originally Posted by macafee2

I cant help but how do you know which vent is open and how do you open and close it?

macafee2

When he says vents,i think he is referring to low, mid and windscreen.

[dattrike]

John,
Have you swapped the unit for a known good one? I can send you one if you need it.

[Number 6]

Originally Posted by dattrike

John,
Have you swapped the unit for a known good one? I can send you one if you need it.

Hello David.I have not swapped anything, It just started doing it

And I dont know how to test the one fitted.

Although I have been sent a way of checking the operation which I have yet to try.

When you say you have a Unit is this the one with the control buttons on?
?

[SD1too]

John; I'm not sure that your system isn't behaving normally but can I clear up a few things which are puzzling me?

Originally Posted by Number 6

Turn on the heater controls ...

Turn on? Do you mean that you are habitually pressing the 'OFF' button when you leave the car? According to RAVE this shouldn't make any difference; the system should still remember your previous settings but it isn't necessary to do this.

Let's just review what you're observing.

Originally Posted by Number 6

The display shows the following.
Temp both sides. Econ and Auto light up, the green light for recirculation comes on. And the fan is running

Just to avoid possible confusion, by "fan" you mean the interior blower don't you?

NO display for which vents are open.

I think you're referring to the air distribution display, in other words the arrows pointing to the graphic of a human body, am I right? If so, that's normal because the distribution is under automatic control unless you press the manual distribution button. Only then does the graphic appear.

To get the Auto light out you need to switch the Green recirculation switch off.

That's normal too. The automatic system has selected recirculation mode. If you manually change over to fresh air intake the AUTO legend in the LCD display will extinguish (that's what I think you mean by "Auto light").

To see which vents are open you need to press the appropriate button.

I think you mean the air distribution display as I've described above, am I right? If so, this is correct. To be accurate, the display only shows to which vents the air is directed. It cannot tell which vents are open or closed because they're under manual control using the mechanical thumbwheels with no indication on the control panel.

So long as your battery hasn't been disconnected, the ATC system will remain active with the same temperature setting each time you start the car. However, the air distribution, blower speed and fresh/recirculation mode will remain under automatic control. To override these settings the manual buttons must be used.

Does any of that help John? Please correct me if I've made incorrect assumptions.

Simon

[Number 6]

Originally Posted by SD1too

John; I'm not sure that your system isn't behaving normally but can I clear up a few things which are puzzling me?

Turn on? Do you mean that you are habitually pressing the 'OFF' button when you leave the car? According to RAVE this shouldn't make any difference; the system should still remember your previous settings but it isn't necessary to do this.

Let's just review what you're observing.

Just to avoid possible confusion, by "fan" you mean the interior blower don't you?

I think you're referring to the air distribution display, in other words the arrows pointing to the graphic of a human body, am I right? If so, that's normal because the distribution is under automatic control unless you press the manual distribution button. Only then does the graphic appear.

That's normal too. The automatic system has selected recirculation mode. If you manually change over to fresh air intake the AUTO legend in the LCD display will extinguish (that's what I think you mean by "Auto light").

I think you mean the air distribution display as I've described above, am I right? If so, this is correct. To be accurate, the display only shows to which vents the air is directed. It cannot tell which vents are open or closed because they're under manual control using the mechanical thumbwheels with no indication on the control panel.

So long as your battery hasn't been disconnected, the ATC system will remain active with the same temperature setting each time you start the car. However, the air distribution, blower speed and fresh/recirculation mode will remain under automatic control. To override these settings the manual buttons must be used.

Does any of that help John? Please correct me if I've made incorrect assumptions.

Simon

Thank you for the reply.

OK then

1 I dont always switch the System off when I leave the car.

2 Fan ==Interior Blower

3 Air distribution, yes pointing to the image of a man

4 Correct

5 Correct again

6 The LCD display always reverts back to Auto plus Econ mode, You therefore need to reset everything again.


I have never had to do this before, It as you said always switched on with the previous settings..

John (Number 6)

[suzublu]

John, have you tried the diagnostic test?
https://www.the75andztclub.co.uk/for...hread.php?t=46

[SD1too]

Hi John and thanks for your patience with my questions.

So it seems to me to boil down to this:

Originally Posted by Number 6

The LCD display always reverts back to Auto plus Econ mode, You therefore need to reset everything again.

So once you've manually changed distribution and/or blower speed, your system isn't remembering the settings when you leave the car and return to it later.

It sounds like an ATC ECU fault doesn't it.

Simon

[Number 6]

Originally Posted by SD1too

Hi John and thanks for your patience with my questions.

So it seems to me to boil down to this:

So once you've manually changed distribution and/or blower speed, your system isn't remembering the settings when you leave the car and return to it later.

It sounds like an ATC ECU fault doesn't it.

Simon

Hello Simon,, I dont know, Any idea where the ATC ECU is located??

Is it seperate to the Main ECU?

John