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Classic49
Joined: 10 Jul 2017 Posts: 4
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Posted: Wed Jul 12, 2017 9:37 am Post subject: Air Horn Connections |
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I am renovating the wiring on a 1934 pre-series Morris Eight which has a pair of wind horns mounted on the front. There is a button on an "accessory" arm on the steering column which creates an earth connection when pushed. However, the horns are already earthed by virtue of being fixed to the body.
Advice requested please on how best to wire these up.
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PAUL BEAUMONT
Joined: 27 Nov 2007 Posts: 1281 Location: Barnsley S. Yorks
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Posted: Wed Jul 12, 2017 1:43 pm Post subject: |
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Hi, Your Morris uses the same "accessory arm" as my Jowett Bradford, I believe. As you say the horn push works by completing the earth circuit (in my case with varying results) are you sure that the horns use the casing as an earth return. If they do I can only suggest that you mount them on insulators and use the earth return from the horn push to complete the circuit. It might be possible to power them through a relay using the earth return to actuate the relay. Whether the response would be quick enough, only experiment would show..
Good luck! |
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peter scott
Joined: 18 Dec 2007 Posts: 7118 Location: Edinburgh
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Posted: Wed Jul 12, 2017 3:26 pm Post subject: |
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I think powering via a horn relay would the safest approach and would also save your push button from the very heavy current that these horns draw.
Peter _________________ http://www.nostalgiatech.co.uk
1939 SS Jaguar 2 1/2 litre saloon |
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Classic49
Joined: 10 Jul 2017 Posts: 4
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Posted: Wed Jul 12, 2017 9:07 pm Post subject: |
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Thanks guys. Some useful ideas. I think replacing the existing wiring is probably the best way forward to also accommodate the supply to the centre fog light. |
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MVPeters
Joined: 28 Aug 2008 Posts: 822 Location: Northern MA, USA
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Posted: Thu Jul 13, 2017 7:18 pm Post subject: |
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peter scott wrote: | I think powering via a horn relay would the safest approach and would also save your push button from the very heavy current that these horns draw.
Peter |
Agreed!
If these are Lucas WindTones or similar they need a good deal of current to make the right noise. A relay is far & away the best & safest bet to get the right result.
Connect the horn button to the ground side of the relay & make sure the horns themselves have a good solid ground. The result should be a loud "Paaaaaaaaaaarp" like a Bentley, not a "fa*t" !
A beautiful & classic sound. _________________ Mike - MVPeters at comcast.net
2002 MINI Cooper 'S' |
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Classic49
Joined: 10 Jul 2017 Posts: 4
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Posted: Sat Jul 22, 2017 9:02 am Post subject: |
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Thanks everyone for the suggestion of the relay - a very sensible idea. Have fitted one with a built in 30A fuse.
The only problem is that, on a 6 volt system, the current drawn by the pair of windhorns was enough to blow the 25A auxiliary fuse in the CFR2 Cut Out. Plan to up to a 30/35A fuse and do some adjustment to reduce the current drain. |
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MVPeters
Joined: 28 Aug 2008 Posts: 822 Location: Northern MA, USA
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Posted: Sat Jul 22, 2017 12:54 pm Post subject: |
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I think you can safely move the main power to the relay direct to the battery. _________________ Mike - MVPeters at comcast.net
2002 MINI Cooper 'S' |
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