My horn is inop and I am pretty sure the switch at the wheel and the horn under the hood is bad.

I have seen on other sites that this was a problem for others but no one ever really tracked down the problem.

I have no juice at the switch under the steering wheel and the horn itself would not work when I tested it.

What is the number one cause for these issue with the horn on the MM?

What is the test procedure to be certain where the issue is. Why would I have no power at the steering wheel? Is there a fusible link under the hood or something I have not found?