Was looking on the net for info on removing the HU on my 4dr saloon and came across this.....something completely different
Disclaimer: I am in no way claiming I figured this out. It does work though.
So if you turn on your defrost windows button for the windscreen (not the heated button for the rear and side) the A/C is automatically turned on with it. The reason being the A/C dries the air which will removes condensation from the windows quicker. It is automatically set because in hotter/humid countries it is the only way to clear the windows.
There is a way to allow you the option to have the defrost on the windscreen and be able to turn the A/C on/off. This supposedly would reduce your fuel consumption when A/C is not needed.
Like most here I bet you don't care why it makes a difference, it's just some more buttons for us to press
So here you go....
a. Turn on the car
b. Put the temp knob all the way to cold & turn the fan knob to off
c. Put the "mode" to the face only location
d. Turn the car off
e. Hold down the Recirculate Button and A/C Button
f. While holding both buttons turn the key all the way to the on position (don't need to start the engine)
g. Keep both buttons pressed, two dashes will appear on the little lcd, then "Lo" will appear when the change has been made. Then you can let go.
h. Turn off the car, then back on and press the defrost button. You should now see "a/c on" on the display and you can turn it off without stopping the defrosting
Let me know if it works for you!!