Horn stopped working

Horn suddenly stopped working. When i set the alarm off the horn sounds then so i know its not the unit. Ive removed the stalk end and tried connecting the two copper contaccts but still nothing. Obviously tried the fuse.
If i hold the copper contacts together and quickly move the stalk around i can get it to work for a few goes and then it stops again
Where do i go from here?
Thanks

Check the earth..

Thanks
Thats the earth from the horn unit?

Yeh, it's attached to the grill surround.. Just clean all connections and the earth at that end.

Thanks