I found the horn in my '79 Catalina, and figured out there are actually two. They hide in the driver's fender, right by the battery. I scraped the contacts off, but they still don't honk when the horn pads are pressed. I suspect they may be damaged from when a battery blew up under the hood years ago. It was left on an old charger and it burst from being overcharged. Could I use a piece of wire and directly connect the positive terminal of the battery to each horn's positive to see if the horns themselves work, or will that risk damaging something?
There should be two spade connectors on the horn, or just one and the horn body. Connect the positive to the spade connector and ground the other spade or the body of the horn (metal) to a metal part of the car. Shouldn't hurt anything. You'll know immediately if it works or not.
From what I could see, there seems to only be a single connector for each horn and they're wired to a bolt in the fender. I was thinking I could take a cutting of wire and wrap it around the space post, then touch the other end on the positive battery terminal. If there's no issue with the horns, they should blare as soon as I make the connection I would think.
If you connect the battery terminal to the horn it wont hurt anything just be sure not to short anything in the process I would recommend disconnecting the horn before you test it
I'll probably pull the relay out, just to be safe. I put an AC Delco relay in, replacing an off brand Chinese thing. That didn't fix it and couldn't find the horns for weeks, so I gave up. I wasn't even looking for them when I found them, lol.