That looks like the Grant setup? Mine kept coming off too. I figured out on mine it takes a lot of pressure to snap it completelty into place. its a very tight fit (at least in my case). If you got an extra one in your kit (like I did) pop it in to the horn button loose and see if that's the issue. If not Scotch tape makes a thin double sided tape that looks just like regular scotch tape that you can possibly wrap one layer inside your button then snap into place?