Navigation device shuts down in case of solar radiation and great heat!!??

I have a Ford Tourneo Custom Titanium Bj 12.13 since 04.14 on which I still have new car warranty until 12.14, My model has the 125 HP machine and otherwise almost full equipment. My problem now occurred for the second time and because of which I have an appointment with my Ford dealer in a few days lies in the following! If the vehicle e.g. in a parking lot stands for longer time in the sun at an outside temperature of today 30 degrees and I start after the start of the engine and the navigator has just programmed to the desired destination and is not yet air-conditioned and the amaturator board and the interior are still very hot, comes after a short time the system messages “system is switched off to cool down”!! Then the navigator and the display also completely shuts off radio and can not be switched on even a certain time anymore!!! This is of course very annoying, since I still in the summer to Italy and there the temperatures are usually much higher than here in Germany!! With a 45,000Euro vehicle this should not be a topic!!! I hope you can help me further and look forward to numerous productive answers from your side. Sincerely Felix.