I find that the reason for the system not operating when you expect it to is not necessarily related to the indication you get. For example, it won't operate if you have the ventilation set to the demist (screen) setting, but the indication will say "A/C" irrespective of whether the A/C is operating or not. And as I discovered during very cold weather, it won't operate if the battery temperature is too low, but the indication was "low battery" rather than "low temperature". Not necessarily suggesting either of these apply in your circumstances, just that the reason might not be the one you expect from the indication. And as you've commented yourself in another thread, trying to work out why it's not working when there are so many arcane reasons is tricky.