ob one said:
it's a surpressor
Thanks OB, is it something to do with the alternator as well, i've been getting problems with that recently i thing it could be faulty going to fit a new voltage regulator over the next few days when it gets delivered.
Took the alternator off yesterday and gave the contact points a clean up, there was some green stuff over the copper windings . Cars not really been used for a year and using it again got some probles, been cleaning up earth points all around then i found this as well