Went to my local dealer and made some enquiries.
The part number (one of a few) I was able to identify for the auto version of the control unit (with chrome trimming) is 7820A072XC, price around 500 AUD + GST. About the same price I paid for a pair of 18inch tyres recently. Given the choice I'd prefer to upgrade my car audio to a chinese nav unit for about the same money. If I could get hold of a used unit for 2/3 of that amount I'd give it go.
According to oogles translation of a japanese website, this control unit is also fitted to the latest generation of Delica D.

 

As luck would have it, I've managed to get hold of an automatic aircon heater control panel (part# 7820A072XC) for half the price of a new dealer part. I posted on a parts wanted site and a wreckers got back to me quite quickly. In fact three wreckers got back to me. Waiting for some spare time to have a crack at fitting it. It seems like a fiddly job as it appears I have to remove some of the front floor console, radio and other stuff in order to get the lower centre console out. I still need to get hold of an interior temp sensor and maybe a photo sensor.

 

I am now even more certain that it has to do with the panel. When you hook up to the Outlander to the OEM diagnostic system, there are outputs like ambient temp, sun sensor, etc. However, there is also an "A/C Panel type." This is not a configurable option as far as I can see, rather, it is reported by the A/C ECU. I don't see why Mitsubishi would make about 3 different types of A/C ECU with only this setting being different (after all, they are all called "AUTO A/C" in ETACS regardless of which one you have and are the same in all service manuals). This field can be one of three: dial, auto, and RHD.
So I am now quite certain that a photo sensor, interior ambient temperature sensor, and front panel are required. An ECU is not required as far as I can see from the manual.

Here is what you need to buy to get a US Outlander to get automatic A/C:
In-car sensor, outlander 2007 $19.59 Hvac - Controls - Automatic temperature controls - In-car sensor Link
Sunload sensor, outlander 2007 $28.63 Hvac - Controls - Automatic temperature controls - Sunload sensor Link
Dash control unit, outlander, w/atc 2007 $367.96 Link

Unfortunately, I can't try it myself because the A/C panel is in Fahrenheit and will be annoying to set the right temperature and sell in the future because people will think its a US car.

 

Thanks again Ivanz for all your hard work. I've not had a chance to make an update for a while. The cabin temp sensor came in at my dealers today (second attempt at getting the right part). Had to come from Japan. I will fit it over the weekend along with a makeshift hose connector that connects from the hvacs blower unit to the sensor. It's a much easier job than fitting the auto a/c control panel !
So far without the cabin temp sensor fitted the manual hvac settings work as before. You can switch it onto auto, the fan kicks in, the fan speed seems to vary according to what temperature you dial in but of course it won't work probably without the cabin temp sensor. I've decided to omit the photo sensor for now and see how it goes.
Will let you know how it goes after fitting the cabion temp sensor.
Cheers.

 

Ah, thanks for the update. Can you get some pictures during installation for future reference?

By the way, do you have an OBD-II scanner? If you got it to think its in auto a/c mode, it should throw this error:
B10C1 Interior temperature sensor system (open circuit)
As you have not yet installed the sensor. If it does, then it is indeed a different ECU that is used and it is not up to the panel. The A/C panel should be relatively easy to install, as it requires only the stereo and a few screws to be removed. You do not need to remove the whole centre console as far as I can see.

 

Alas, I've already installed the a/c panel and now also the temp sensor. Sorry, I don't have any pictures. I've not bothered with the sunload sensor. I think the system is working. The ecu seems to be trying to control the cabin temperature to the preselected temp setting. I've only managed to do some limited testing as yet. My wife mainly drives the car. I don't have access to an OBD-II scanner (I'm looking out for one, ELM327 seems to be fairly popular). Can you get ecu error codes out without the use of a scanner ? You used to be able to with my old Nissan (engine light would pulse out the code when you shorted a couple of pins on the obd connector). The weather is cool where I am so the system is working mostly with heating. Maybe I'll get hold of a seperate thermometer and monitor more closely. I used the schematics from the service manual to determine which panels / screws to remove.
Like you say Ivanz, you might be able to gain access to the a/c panel's four retaining screws by reaching behind down the hole where the radio sits. I'm not so sure. My hands aren't that small and nimble. I did the installation the longer way as follows;

1. Referring to the 'Instrument Panel Assembly Removal and Installation' section of the service manaul, remove vents (be brave and pull forward) from the sides of the radio. These types of retaining clips are used throughout the vehicle.

2. Remove the two exposed screws holding the radio / cd panel.

3. Remove the top screws holding the top of the lower centre console (labelled item 18 on the manual).

4. (Right hand drive vehicle) Pop out the side vent to the right of the steering wheel.

5. (Right hand drive vehicle) Pop out the drinks holder just below the right side vent to the right of the steering wheel.

6. (Right hand drive vehicle) Remove the Side lower panel assembly (labelled item 17 on manual below steering column). Its held on with 2 screws at the bottom (remove bottom cover first), and clips at the top. You'll have to be brave to pry the panel out of its clip retaining holes. This will expose the cabin temp sensor holder, wiring and lower centre console right retaining screw. Undo the screw.

7. Referring to the 'Front Floor Console Assembly Removal and Installation' remove the left and right lower side covers.

8. Pop out the front drinks holder (labelled item 3 in the manual), and partially pull up the 4wd selector and drinks holder panel to allow you to gain access to the screws that are holding the front floor console (labelled item 4 in the manual) and lower centre console.

9. Remove the lower glove box door and remove the left lower centre console retaining screw.

10. By now you should have been able to remove enough panelling to free the lower centre console (pulling it forward) and gain access to the a/c controller 4 retaining screws.

11. Of course installation is the reverse of the removal process. Before fitting the side lower panel assembly (labelled item 17 on manual), you should easily be able to install the interior cabin temp sensor and a piece of straightish slightly flexible tubing that connects it to the hvac connector which is located a little further back into the dash (about 10cms).

That's all I can remember for the moment. I'll keep you posted on the performance of the upgrade. Cheers.

 

Thanks for the step by step guide.

Nope there isn't any way to read codes as far as I know except by using an OBD-II scanner. Since you installed the sensor, the code will probably not show up anymore. I was hoping it would confirm the A/C ECU was indeed the reason for automatic A/C, since only the automatic ones throw this error.

So did you figure out what the key was to upgrading? The ECU, panel, or just the sensors? At least we know it isn't the main ETACS ECU...

 

Rex
I have the 2009 ZG LS 2.4 CVT with LPG with the auto aircon. No real advantage as you have to manually adjust it all the time anyway because the fan can get very loud. I live in Aus as well.

 

You need the upgraded a/c panel to send the required user selected 'auto' signals to the a/c ecu and the cabin temp / sunload sensor to give the a/c ecu feedback.
If you could figure out the protocol of the 'auto' signal you could configure a seperate switch to do this instead of forking out for the upgraded panel.

I'll probably get hold of the sunload sensor before summer comes around.

Thanks for comments callross56. I can't say I've experienced a noisy fan as yet. Maybe by the time summer comes around, it might be a different story. The reason I've done it is because I'm fed up of having to constantly fiddle with the controls cos its either too hot or too cold. If you don't mind me asking where did you get your LPG conversion done ? My handbook states that its not supported by Mitsubishi. Does it void your warranty ? Where is the lpg tank installed ?

 

Ah, I knew it was the panel. There was no seperate A/C ECU number for the Lancer or the Outlander, so it was the logical conclusion

The protocol is likely the CAN Bus (or LIN bus, which is a subset). If somebody has the time, patience, and money they could build a touchscreen CarPC with a canusb adapter to adjust all the settings. Since everything goes through the CAN Bus, you can virtually control anything from there. This means anything from engine RPM to windows, doors, stereo, etc. Although these are 3 seperate buses, so you would need to get 3 of those adapters to control everything ($100 each).
Newer Lexus cars have touchscreen A/C controls, which could easily be implemented on the Outlander as well with the above.