Sometimes a problem can be caused by the tiniest thing. This was the case with my DeLorean’s horns – one of the two had stopped working so I was only hearing sound from the front left corner of my car.
Horns on a car are legally required to make a sound that resonates in two frequencies. Part of this is because some people have hearing difficulties in certain bands of the audio spectrum and it might just happen that they can’t hear your horn’s specific frequency, but also because if it was a single frequency there’s a chance that a car’s windows or body panels may attenuate that single specific frequency. But with two frequencies, the resonance between them creates harmonics that makes the alarm not only sound louder than it is, but because it’s now spread out over multiple frequencies there’s a much higher chance it will get through windows or body panels and it’s less likely someone will have hearing damage across all of its harmonics.
Some new cars have a single horn unit that operates on two frequencies, which is cheaper when made as a combined unit, but many older cars as well as large trucks just have two separate horns. Separate horns are simpler in their construction, they can usually be louder, and you can position them in different corners so the sound travels around your whole car better.
Sure I could just buy another one since it’s only $20 for a New Old Stock one, but I wanted to see if it was repairable. So I opened it up to see what was inside and wouldn’t you believe it… A single piece of grit was resting between the contacts, preventing them contacting & completing the circuit. That’s it – a single speck of the wrong kind of dust in the wrong position and it stopped working!
I wiped down the horn’s internal components, reassembled it, and I also took the opportunity to clean the connectors of both of my horns – 35 years of corrosion does add a reasonable amount of electrical resistance, which makes for lower voltages & quieter horns. The end result – my horns now both work, they’re both louder than before, and I didn’t have to pay a cent to replace any parts. Score! 🙂