My horn on my 93 only occasionally works, probably 30% of the time. I have an aftermarket momo wheel, hub, and horn button.

I took the wheel off to check the connections, the positive from the original connector to the momo horn button seem solid. It has grounding plate with a cable running from the negative on the button to the plate.

When I press the button it's seemingly random, it will work several times in a row then go 10+ times not working.

I've connected a multimeter to the +/- on the button to check for a complete circuit via the ohm setting that seems to work consistently when I press the button. I'm no electrician so I'm not certain how concrete of evidence that is.

I've also taken a piece of wire, wrapped in electrical tape, and grounded the positive to the wheel hub and the horn is will go off seemingly at random. This may be because of a poor ground though.

Since it sometimes works, I think that rules out fuses and the horn itself....so a wiring issue? Bad ground? Bad button?

I'd appreciate any insight. Some pics attached.


Aftermarket positive line from original connector to horn button

Horn, held in place with all wires attached, will work ~30% of the time.

Positive line from original connector to horn button (not attached).

My "test" where the horn is intermittently working, no more than a half second at a time.

 

Ok I did some more investigating. Based on my doctorate in Google, it can be 1 of 5 issues.

1. Horns - not it, works intermittently.
2. Fuse - not it, shares the STOP fuse and my brake lights work.
3. CPU - probably not it, same logic, would either work or not work, nothing intermittent. Not 100% though.
4. Relay - maybe? Not sure yet where the relay is...
5. Wiring / grounding - don't think this is it. When I ground the horn wire I can consistently hear a clicking sound. I get a honk like 25% of the time.

Does this sound right? The intermittent nature has me stumped.

Thanks in advance for any insight!

 

To me it sounds like a loose connection. I would start at the horns themselves and check the pins to ensure they are clean and tight. This will also allow you to check for source voltage with the horn button depressed. Ensure you are getting source voltage to each horn.

Any time aftermarket parts are installed I typically look to them as the culprit. The electrical system is pretty good from the factory. I look at whats been altered and ensure that the horn contacts are goot at the horn button. The horn is a ground side control so it will have voltage but needs a ground to complete the circuit. When you depress the horn button you touch the grounding plate to the contacts and this is what completes the circuit to power the horns.

 

@mazdaverx713b thanks for your response!

Great point about "what has changed". The previous owner states that the horn worked consistently, and I have not done any mods to to the wheel or horns.I did add HIDs and the ballasts that come with them, but other than maybe jostling the lines to the horns I did not touch them.

I do have a v-mount and as such it's a pain to get to the horns, but it sounds like thats my next step.