That is a very interesting piece of information Malcolm, and something of which, as you may now guess, I was quite unaware. Big brother knows better! But I do have to say that it probably is quite a good idea really, as a good proportion of air conditioning problems are the result of extended lack of use of the A/C function. Such systems, like the lane deviation systems that I loathe, are, of course, generally designed for idiots and bad drivers, not Diesel Car readers! As you say though, this automatic air conditioning turn-on feature really should be pointed out in the handbook. Thanks for the information though. I believe that more recent Climatic systems have now dumped the temperature markings (18, 22, 26) and just now have a knob that rotates between blue (minimum) and red (maximum) which presumably still represent the same temperature ranges. Thanks for the info, Malcolm.