Welcome, rj. I am restoring a 306H. Both of our trucks have a lot in common from the cab forward. I will be dealing with the horn button on my truck real soon too. If you don’t get an answer from someone on this forum. I have a contact in Texas that has been very helpful. His name is Tom Warren and his family is in the business of restoring Diamond T’s. If you need any rubber parts, he is the source I used. He has everything that is made of rubber. Everything else, he has a source or an answer. I am doing a full restoration from the frame up. This weekend we will be painting the frame. Next, we will be working on the wheels and the brake systems. I have set a goal to have this truck ready to roll through a parade this year on Father’s Day. Where are you located?