Meriva 1.4 petrol completely blacks out occasionally. Everything goes dead. First time called AA and technician disconnected and reconnected the battery. Started immediately with no sign of previous blackout. As both parties were in a hurry, we split but as a parting shot AA man said "put a10 mm spanner in the car for the next time". There have been about 3 "next times" since and the AA fix always works. But what is it? Any ideas.
