Using horn from later model Chevy on my 1969 truck

[dmjlambert]

Using a horn from a later model Chevy means the horn will not have an old-fashioned blade terminal. The newer ones have a plastic clip socket and I found the clip plugs with pigtails to be expensive. So, I created my own pigtail adapter so I can use a common blade terminal to hook into the wiring harness connector.
First, I wrapped the stripped end of a short piece of wire around a small nail. Then I tinned it with a soldering iron, and pulled it off the nail while still hot. I tinned the horn's terminals, then slipped the prepared and tinned wire onto the terminals while heating it. Finished by heating the connection with the soldering iron and adding more solder. Repeat for the other terminal. It takes a little finesse to avoid melting the connector plastic while soldering because the terminals are way down inside. One wire gets a blade terminal, and the other wire gets a ring terminal to connect to the bracket for ground. Fill the horn connector with RTV. Done.
This horn is from a 1999 Chevy Astro Van.

[VetteVet]

Necessity is the mother of invention.\
Combine that with innovation and talent and we have Mr Dmjlambert.

[dmjlambert]

I did find one of the horns had a messed up adapter (1st picture) or messed up soldering job of mine. The high horn sounded horrible and only lasted a few toots. Horn did not work with my adapter on, and did work when connecting directly to the horn contacts. So I left the adapter off, wrapped the stripped wire around a larger nail, and soldered it directly to the horn contacts. Filled the horn's connector with RTV. Looks fine and works well when installed. That is probably a more elegant way, because now I have fewer connectors and better connections. Now I have a two-note system.