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Horn should work but it doesn't

Posted: Thu Jul 01, 2010 10:17 pm
by culp
Hi

I have a Series II with the original horn (and the original wiring!) The horn doesn't work. I've been through the circuit and as far as I can tell it should. Here's what I've done
  • Battery fine
  • 12 volts at one side of the fuse (the top one terminals A one and A two)
  • 12 volts at the other side of the fuse
  • tested the fuse with a resistance meter, fine
  • 12 volts at both terminals on the horn
  • 12 volts at the spring clip under the dash
  • 12 volts at the horn push
  • horn push earthing correctly
  • removed th horn and temporarily wired it the to battery, lots of noise
What the hell? Surely the horn should work

It's all that's needs doing for the first MOT test in 20 years. Surely there is a logical explanation somewhere

Help!

Re: Horn should work but it doesn't

Posted: Thu Jul 01, 2010 10:35 pm
by PSL184
I'm not sure about Ser 2 horns but you mention 12volts at both horn terminals - Is one terminal not earth and if not how is the horn earthed?

Re: Horn should work but it doesn't

Posted: Fri Jul 02, 2010 10:29 am
by bmcecosse
The horn push is obviously NOT earthing correctly! Try earthing it there with a wander lead.

Re: Horn should work but it doesn't

Posted: Sat Jul 03, 2010 10:51 pm
by mike.perry
Test the horn by disconnecting both wires at the nearest bullit connectors and run substantial feed wires from the battery teminals to the horn wires. Alternatively you can remove the horn and connect the wires to a battery charger. The horn consumes a heavy current so the wiring needs to be in good condition.
If the horn does not work then there is an adjuster screw in the middle of the horn. Try adjusting it one way or the other
If the horn works OK then check the contact on the brass ring below the steering column bracket.
Check the screw holding the horn push to the steering wheel boss is tight
Also check the wire inside the horn push is tightly held by the small nut

Re: Horn should work but it doesn't

Posted: Sat Jul 03, 2010 11:09 pm
by bmcecosse
He already says the horn makes lots of noise on the battery.........

Re: Horn should work but it doesn't

Posted: Sun Jul 04, 2010 6:57 pm
by culp
Thanks mike.perry that pointed me in the right direction. It turned out to be a broken connection for one of the terminals in the horn, worked some times and not others...wiggling the wire around tracked it down. It's a shame the horn has rather had it so I've bought a new one, horrible plastic thing not the great substantial piece of steel, brass and rubber from the original.

Re: Horn should work but it doesn't

Posted: Sun Jul 04, 2010 7:18 pm
by mike.perry
Keep a lookout at auto jumbles etc and you should be able to pick up a good original type Lucas Altette horn. Just check that it is 12V not 6V. Or you may get a pair of Lucas Windtone horns. Try "Taff the Horns"