Author Topic: Problem with horn wiring.  (Read 3000 times)

Offline ted_paper

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Re: Problem with horn wiring.
« Reply #15 on: January 04, 2025, 11:00:12 AM »
Cheers guys

Offline Bryanj

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Re: Problem with horn wiring.
« Reply #16 on: January 04, 2025, 11:48:40 AM »
Turn the knob to the left till the arrow points to the white mark with 20 on it, if you connect the red lead to positive battery and black to negative battery it should show about 12v, you then leave the black on the battery and test for voltage at various points, still need to know what wires go to horn button to be exact and is the same button a headlamp flash as well

Offline ted_paper

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Re: Problem with horn wiring.
« Reply #17 on: January 04, 2025, 12:46:32 PM »
Managed to sneak into garage for 10mins.
Reading is around 12v
Split L/H switch photos attached

Offline Bryanj

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Re: Problem with horn wiring.
« Reply #18 on: January 04, 2025, 02:27:34 PM »
Pic dont help, need to know what colour wires go to horn button

Offline Bloggs

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Re: Problem with horn wiring.
« Reply #19 on: January 04, 2025, 05:30:50 PM »
Ted,

Where are you located? There might be someone  local to you who could help.

Michael

Offline McCabe-Thiele (Ted)

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Re: Problem with horn wiring.
« Reply #20 on: January 04, 2025, 05:38:27 PM »
Managed to sneak into garage for 10mins.
Reading is around 12v
Split L/H switch photos attached

Where did you take the 12v reading from?
Honda CB400NA Superdream (current money puddle)
Honda CB500 K1 (second money pit)
https://www.sohc.co.uk/index.php/topic,28541.0.html
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html
This is a neat 500 restoration in the USA.
http://forums.sohc4.net/index.php/topic,151576.msg1731556.html#msg1731556

Online Mikep328

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Re: Problem with horn wiring.
« Reply #21 on: January 04, 2025, 07:58:15 PM »
If there are TWO horn wires, connect the black probe to one and the red probe to the other.  Turn on the ignition and press the horn button.  You should see "battery voltage" (12-13V) on the multimeter.  You might see - (minus) voltage but that doesn't matter in this case.  It just means that you connected the red lead to the negative (earth/ground) wire instead of the hot wire.  Makes no difference for this test. 

Offline ted_paper

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Re: Problem with horn wiring.
« Reply #22 on: January 06, 2025, 03:08:00 PM »
Solved!
Thanks to the advice given, I traced the problem back to the spade connectors.
When trying the probes, one to the connectors seem to "wobble " a bit more than I expected so I gave it a gentle wiggle and it come off with few millimetres of wire. Did the same with the other and the same result. I managed to remove a small piece of sleeving to reveal the wires and the bulb test worked!  :)
I just need to cut back a bit more to try and extend the wires to the correct length.
The only strange thing is that both of the spade connections show signs of melting.....
Thanks for your patience and all the help given.

Offline Sesman

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Re: Problem with horn wiring.
« Reply #23 on: January 06, 2025, 03:37:12 PM »
I’m guessing that the poor connection created a high resistance joint resulting in the production of excessive heat, which is unusual given the normal type of horn use. Oddly enough my horn connections show similar signs of heat distortion, but not to that extent.

Offline McCabe-Thiele (Ted)

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Re: Problem with horn wiring.
« Reply #24 on: January 06, 2025, 04:46:03 PM »
Proximity to a hot  engine/exhaust pipes doesn't help.
Honda CB400NA Superdream (current money puddle)
Honda CB500 K1 (second money pit)
https://www.sohc.co.uk/index.php/topic,28541.0.html
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html
This is a neat 500 restoration in the USA.
http://forums.sohc4.net/index.php/topic,151576.msg1731556.html#msg1731556

Offline Sesman

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Re: Problem with horn wiring.
« Reply #25 on: January 06, 2025, 06:18:36 PM »
Aye, certainly a possibility if not a probability.

 

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