I think I am losing my marbles. Doing relays for the headlights and horns. 3 each side. Relays in sockets - two light leads to fire the coil, two heavy leads for input and output. Picked one of the light leads (85) as trigger to be connected to original power feed; other light lead (86) to go to earth, so I connected all 3 leads together at an eyelet/ring. Fed the 30 lead from a small fuse board fed from the heavy lead at the light switch. Fitted bullets to the triggers to connect to the old leads to the lights, and bullets to the output 87 leads to go to the lights. Connected everything up EXCEPT the earthing of the 86 side of the coils..... and the lights worked.... without the 86 being earthed..??? I cant see that tying the 86 leads together is a problem, as they would all have to go to earth somewhere eventually. The lights work correctly, dip and main. For the mains I used one of the two original feeds to fire the relay, and fed both lights from the one output, and left the unused feed inside its insulated connector.
Any ideas how the relay is firing ?