Still having problems with horn working on 1972 GMC

[Jobe72]

Ok gang,

I've done everything I know how to do, checked everything I know to check but I still can't get my horn working in my truck.

Worked fine when I got the truck 1.5 years ago then slowly it stopped working altogether. I've replaced the horns, checking the wiring for a short, replaced the horn hardware and the relay.

Currently it either does nothing or makes a buzzing sound at the relay.

I'm about to put my own horn button in the middle of my center cap and call it a day but thought I would try one more time to get the factory one to work. My truck is out of inspection because of this and it's my daily driver.

Thanks for any help you can give me
Bryan