Harley has made a lot of changes to their motorcycles over the last 100+ years, but in all that time, one thing has stayed the same, the horn button has always been black. Sure you can get chrome covers for your late model buttons, but for us vintage guys the options have been black, black or black. So when I saw some custom colored horn buttons on Instagram, I quickly reached to @knucklejunky to see what they were all about.
Look carefully and you will see that there are two slots cut into the sides of the horn button assembly. These hold a piece of copper sheet metal which keeps the horn's internals together.
Using a small screwdriver, gently pry one of the tabs on the copper bracket out of the slot. Make sure you don't bend the bracket since replacing it requires rewiring the horn button.
Now the horn button's internals can be completely disassembled and the original black button can be removed.
Drop the new button into the horn button assembly (it only fits in one way).
The upper brass contact comes next. Note that it is designed to fit inside the spring, so it does matter which side you leave facing up.
When installed correctly, the spring will slip over the brass contact.
Push in the lower contact and reinstall the copper bracket to hold everything together. At this point you will be tempted to test your new button and will be disappointed when it doesn't work. Keep in mind that the horn button will not work unless the assembly is grounded (typically through the handlebars), so be patient and wait until you have completed the installation before testing.
Lastly make sure to carefully push the excess wire back into the handlebar and reinstall the two screws.
@knucklejunkey makes buttons in four different colors (red, yellow, green and blue) so finding one that looks good with your paint scheme should not be an issue. If your not on Instagram, you can reach him via email at firstname.lastname@example.org.