Here is where I will have you all beaten! You do NOT want to get into any "Gordon Badwrench" contests with ME!
My horns have not worked since I got my car last month. Just a quiet "purr" out of the right one. The previous-previous owner had done all the work on the car. Since it involved rack and pinion steering, new wiring had to be installed for the horns.
The PO said that I needed to straighten out the ground.
You could hear my car groan, "Oh $hit, here he comes and he's got his TOOLS."
Anyway, I know that the system has been changed to negative ground. I cannot tell which wire off the horn is ground or live, as one goes up the steering column and one disappears into the harness. So, I got out my jumper cables to see if the horns work if wired straight to the battery. I cut out a solder splice on two wires, stripped them, and twisted them together. I GUESSED that they were the ground. I hooked up the positive jumper cable to the other solder splice (three wires), then lightly tapped the ground cable against my new splice. No sparks, so I hooked on the cable and hit the horn button. Voila! So, the horns work. I took the ground cable off the battery and touched it to a screw on the dash and the horns worked.
Now it gets interesting. I attached a new ground wire to the screw on the firewall, twisted it around my twist splice, and put a twister cap over the splice. Then removed the jumper cables. I hit the horn button. THERE HAS NOT BEEN SMOKE LIKE THIS SINCE THE CHICAGO FIRE!
I figured "no way" did I attach my ground wire to the wrong splice. So, I removed it, and just TOUCHED it to the other splice and the horns sounded! Without the horn button being pressed!
So, Gordon has struck again. WITH ONLY TWO WIRES, he has the option of an engine fire or a permanent horn blaring. At this stage, the fire seemed the preferable of the two, as it would not disturb the neighbors.
So, I said the heck with it, and unhooked my new ground wire from the splice, and put the screw cap back on the splice. Remember, I have not touched the other splice. After all is said and done, I get in and try the horn button. The horns are loud and clear.
I have no @#$%^&*&^%$#@#$%^&* idea why they work. The only change has been that I replaced a solder with a screw cap.
And, of course, the Zen question of the day, is WHY WHEN I HOOK ANOTHER GROUND WIRE TO THE GROUND SPLICE DOES A FIRE BEGIN?
Now, who here wants to contest me? Warning, I will next hit you with my breaking the heater core out of my 2-week old new Miata while installing a $2 Prestone Radiator Flush Kit: $550 - would you like my ex-wife's phone number?