cust a long story short, changed headlight bulb about a month ago, wife driving home in the rain, heater, elect windows rear wiper etc all stopped working, rang ford dealer mentioned change of bulb etc may have knocked earthing wire below headlight. Fiddled with it, started working ok until yesterday, driving in the rain again, same thing, heater, heated front screen etc all gone off fiddled with light again did'nt work this time. Obviously wet weather seems the problem any suggestions ???

 

is there rust between the earth strap and metal of the car ?