Ongaro twin trumpet horn problem

[Bridgeman]

Our Ongaro twin trumpet 12v horn stopped working. I cleaned the points etc and now it is working great. Only problem is it only works from helm position switch now and not flybridge switch. Worked from both before it packed in. I have had a look at switch and seems clean and dry. Anyone had this problem or any idea what fault may be please?
Just for interest if any other forum members like me new to boating I got info on cleaning horn from Ongaro who were very helpful,but had no idea what problem was with switch.
Thanks.
Neil