Topic: 1967 GT500 Horn Button

[kkupec02]

Still working on my electrical problems. One at a time. I had no horns when I bought car. I replaced the column harness and repaired the shorted wire in the steering wheel. I have been worried that I didn't know what caused the short in the first place. Now maybe I know. I was putting it back together today. To preface, I disconnected and reconnected battery before and after each test. Connected the two horn wires manually before I attached horn button but after steering wheel installed. Horn blew. So contacts good. Connected wires to horn button and used outside of steering wheel. Horn blew. Installed button into steering wheel. Horn blew sporadically and sparks flew. Took horn button out of wheel and horn blew with no sparks. While blowing horn as a test, side of horn button accidentally touched steering wheel and sparks flew. But, where it touched is how it mounts to wheel. Seems like button is somehow grounding to wheel? Hate to have to replace original button, but somehow seems volts leaking from button into steering wheel cradle. Can it be fixed or do i need to buy a repro button? thanks.     

[kkupec02]

ps. I have it apart but don't see anything that would cause unwanted contact with the steering wheel. I'll have to do some continuity tests to see if i can find the ground.

[67350#1242]

There is a spring inside the horn button that should have plastic insulating sleeve over the bottom coils that insulates the contacts from the metal body.  Ones I've seen are a red sleeve.

[kkupec02]

The spring is green rubber coated on the lower half and seems fine. No scorching. Can't visually see where a ground short may be to horn button rim. 

[67350#1242]

I would check for shorts from each pin to the body of the horn button with ohmmeter.  Assemble the button and check again.

[kkupec02]

The person that I bought the car from had it apart and couldn't fix the horn issue and sold it as is. I see no exploded view diagrams. Which side does green coated copper spring face? Metal plate side or plastic cap side?

[67350#1242]

From memory the larger insulated end goes toward the metal plate with the contact arm reaching over one of the insulated coils. (slide the spring under the contact arm).

[kkupec02]

Thanks. I think the spring was reversed or not under the contact arm but need to figure out where the copper washer goes. Despite me being careful it kind of fell apart in my hands. I don't see any diagrams online.   

[Bob Gaines]

Thanks. I think the spring was reversed or not under the contact arm but need to figure out where the copper washer goes. Despite me being careful it kind of fell apart in my hands. I don't see any diagrams online.

And unfortunately most likely you will not so don't beat yourself up too bad or spend too much time before going to plan "B".  What ever plan B may be for you.

[67350#1242]

Copper washer is on top of spring and fits over the stud on plastic button, keeps the spring centered.

[kkupec02]

I should have attached a picture. I do not know if the guy before me had it assembled right. Probably not. I have insulated wire under contact. Smaller part of copper washer facing towards contact so it can be pushed down. Larger part of copper washer fits into plastic part of button. Thanks a lot for the help.   

[kkupec02]

Thanks 67350 and Bob Gaines. I found that the problem wasn't the horn button. The factory hole in the steering wheel hub where one of the wires came out had a burr in it and over time put a small pin hole in the wire. When the horn was pushed, sometimes the exposed wire touched the steering hub and shorted. That was probably what blew the horn wire that I had to replace in the steering wheel and the column wiring harness that I had to replace with the burnt horn contact. Next I move on to my light and low voltage problems. But, I am happy that I am getting help here and making progress. Thanks again.