I am very curious about an electrical fault which affects my Insignia. When I pass a particular spot on the M1, the temperature gauge goes to zero, and the dashboard displays the message "air con not working due to high engine temperature".

This state can remain for weeks and then without warning will reset on its own. I have taken it to the dealer twice, and they can't trace the fault. I therefore have to avoid this spot on the M1 and take a detour. Any ideas?