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Horn Quit Working

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Bobbee44

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Just when I needed it...morning driving in Washington, DC, the horn decided not to work. Is the horn on one of the two fuses against the firewall?

Thanks,

Bob
 
On your engine compartment firewall, there are just two fuses. Check them first. If your stock and you have not added inline fuses, you do not have an additional fuse for the horn. If its not working and your fuses are ok, Im thinking it may have unplugged at the horn itself. Theres two, and both have two leads. Pull them, clean them, then add some grease to the ends and plug back in and try. If no, then it may be time to break out your wire tester....

Bobbee44 said:
Just when I needed it...morning driving in Washington, DC, the horn decided not to work. Is the horn on one of the two fuses against the firewall?

Thanks,

Bob
Click to expand...
 
That's dielectric grease! If you don't have any just make sure the connectors and wires are clean and bright.

Check the other end of the horn harness where it goes into the main harness too. It should be in the vicinity of the radiator mounts if I remember correctly. The bullet connectors get pulled out quite easily if they're not seated firmly.
 
The lead that fires the horn--don't remember if it's to power or ground--goes through the steering stator tube and comes out at the front of the steering box. Check it (don't know the wire color, but I think there's four leads--check them all).
 
Link works well. I am going to get out and get under this weekend in an effort to "fix" the horn issue. Thanks for all the advice. I am hoping it is a fuse, but with my luck it will not be.

Bob
 
Hi Bob,

Having the horn stop working is not uncommon and the probability is that you will find a displaced or corroded fuse. The horns require high amperage and is the only units serviced by the larger (35 amp US fuse or 50 amp Lucas) of the 2 fuses within the fuse-box. With this in mind and considering that, when activated, all operating power must pass through the horn button switch (located at the top of the steering wheel/column) and a number of connections before reaching the horns, it is not difficult to realize that this is a unit that could be prone to failure. Add infrequent use to this setup and a failure will probably go unnoticed, or even considered, until the horn is actually needed.


Over the years I have installed a number of relays with easily-hidden in-line fuses to offload high amperage units (i.e. head and driving lights, etc.) from their original dependencies (undersized wiring, switches, connectors). Since the horn gains its power after it as passed through the horn-button switch and a number of bullet connections and wiring that is marginal in gauge at best, you may want to consider installing a relay behind the horn in order to provide reliable switchable power more directly to the horn while reducing amperage passing through the horn-button/steering column to only that needed to trigger the relay.


However, since I had installed this invisible alteration some time ago, I must admit I can’t remember the last time I blew the horn. Given this infrequent use, and should you not want to go through the effort to install a relay, I would agree with what others have suggested and, at a minimum, suggested you clean and solder all wiring ends and coat all connectors/connections with dielectric grease.

By the way, I have been told that, in the absence of dielectric grease, Vaseline can be a substitute. Has anyone else heard this?

Good Luck,
Ray (64BJ8P1)

 
RAC68 said:
I have been told that, in the absence of dielectric grease, Vaseline can be a substitute. Has anyone else heard this?
Click to expand...

Hi Ray,

Anything greasy is a 'dielectric' grease in the context of 12V systems. The term dielectric is a complete misnomer in that we aren't trying to prevent insulation breakdown but instead we are trying to exclude oxygen from the metal surface to prevent corrosion interfering with the connections. When used in it's intended application such as spark plug boots, dielectric grease won't break down to form carbon tracking paths because it doesn't contain petroleum/hydrocarbon oil.

The problem for us is that petroleum based greases including Vaseline will swell the rubber sleeves on the bullet terminals. You could equally use rubber grease which is castor oil based.

Andy.
 
Hi Andy,

Thanks you for the thoughtful clarification.

Although I have not found it necessary to use Vaseline on any connector in my Healey, I have used it on the connectors of my son’s lawn tractor and found it to perform with no issues. Since a lawn tractor’s electrical connections have a propensity to corrode from the intrusion of moisture, all connectors have been coated with Vaseline before connection was made. Since no coated circuit connector handles high amperage and all contact boots are plastic, I don’t expect that carbonization or boot expansion to take place … or should I?


Thanks again,
Ray (64BJ8P1)

 
Hi Ray,

Just to clarify, it isn't the current that causes problems with oil based greases, it is the voltage. Anything that uses thousands of volts (kV) such as ignition wires and inside the back of old TV sets is prone to arcing through paths formed of conductive dirt. The 'proper' use of dielectric grease is to seal up places where HT can leak out without worry about the grease itself causing more tracking paths to form. It just so happens that dielectric grease is ideal for bullet terminals too because it doesn't contain oil.

Vaseline is perfect for connectors that don't use rubber sheaths, works very well on battery terminals too.

Andy.
 
Thanks to all respondents. The horns were not wired correctly, a product of exceptionally poor craftsmanship on the part of the person(s) who allegedly "restored" the 1960 BT-7. The horn, in conjunction with any number of profoundly poorly executed repairs, has cost me dearly in time, inconvenience and, above all, money.

The horn (low note) is operating well. The high note horn is inoperable.

All this to say shame on me for having put too much faith in a "reputable" auto sales company.
 
Open it up, most of the time there is just little damage at the points
Clean, adjust and honk ;-)
 
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