Hi Doug,
The relay is in the engine compartment mounted on the tool box housing at the front, the engine management box is mounted on the top of this tool box.
That idea did cross my mind so I moved the relay to about a foot away but this made no difference. I also had led bulbs in the wing top mounted side lights (where I picked up the feed for the relay) so I replaced the original bulbs which are 5 watts each as I had an idea that perhaps the led's didn't have enough resistance and allowed the spike to happen, but this made no difference either.
So we are now at the point where I have run out of ideas.......
Rob....
