I have had an intermittent horn for a while. Checked the wiring and the relay.All OK so thought it must be the stalk switch. Took it apart and the gap between the two brass contacts had grown to 4 mm since the prototype was built in 1988

Polished the tubular brass contact in the stalk end knob on the right - no improvement - so closed the gap between the brass contacts to 3mm as on a spare steering column multiswitch in stock. Go closer than 3mm and you will have a horn that is permanently on When you reassemble the stalk the button must line up with the slot on the stalk end and be pushed straight on or the brass contacts can get bent



I now have an excellent horn in every stalk position. In fact the fastest horn in the west !

Once again, many thanks for yet another tip Dan.