just thought I would pass this on. It may or may not be usefull.
I have a motorcycle, 15 years old and in good condition. Every year I put it away for the winter. Before putting it to bed I clean and lub it up. Then I cover the bike ( not the brakes etc!!) with ACF50. As stated the bike is 15 years old and looks in better condition than some newer bikes.
OK to the point - I make sure I coat all the electrical cables and connections. I have done this to my focus engine bay aswell, and in my ownership neither has had an electrical problem. OK I appreciate I could be lucky, but ACF50 is a water repellent. It is supposed to protect for a year, and I feel more confident with it than say WD40.
I cannot guarantee that the ACF50 has worked but for a £10 tin it cannot hurt.
With the car I just sprayed it liberally over most of the bay. Obviously concentrating on the electrical parts. The product is suppose to coat the items and form a seal. Any on the engine or hotter parts just burns off. However, it does still protect these areas. ( Note the spray does smoke a bit until it burns away, if you try it, well ventilated area required! :-) )
Prevention is sometimes better than a cure.
hope this is useful.