Check the earth wire first,i had the same problem,worked then it didn,t the end of the earth wire had got hot and was black cut it back,put a heavy duty ring connector on and nut and bolted to the motorhome floor (has to be steel not wood)lol
------------- Think this year is to follow old meet friends for 2014.
If you cant do someone a good turn,don`t do them a bad one,its nice to be nice you know,and little things mean much more later in life.
Pete.