You get power from your wire and you get ground from where the horn attaches to the body. Be sure that your horn is grounding properly where it screws into the body. Ensure there is clean metal on both sides of your ground and power. Also be sure your horn relay is working.

I have only been unable to repair 1 horn and that was because I took it apart. I have brought all of my horns back to life with PB Blaster soaks.

Disconnect the horn
Take note of how many threads are showing on the adjustment screw
Run out the adjustment screw
Spray PB Blaster in the hole
Let it soak a day or two
Rinse with brake cleaner\degreaser
Run the adjustment screw back in to the height it was and try to sound the horn
If the horn is low or still not working repeat the process for a few days


After you soak your horn and clean it re-install it and run the adjustment screw 1/8 turn at a time. It is way easier with two people (one at the horn and one at the screw). At first you might get a squeal but by adjusting you'll get a louder sound, if you go to far it will start to squeal again.


Your ground metal can use a good wire brush based on the pictures. Also DO NOT connect Directly to your battery you will kill the horn (that is why you have a horn relay in your vehicle).