horn issue

How do I remove the metal ring? and where can I get replacement plastic ring? I guess I could always try and get it from one of teh other wheels I have.
When I get home tonight I will check it out with and meter.
Thanks again

The plastic was molded to or with the copper.
It is so brittle today that you likely wont get the ring off of any wheel without destroying the plastic.
Once you get the ring off you could rebuild the plastic with Plasti-Cast or some strong epoxy.
Knock the ring back on with a line wrench.