Lotus Elan

Horn problems

PostPost by: TonyWalker » Sat Nov 19, 2022 6:00 pm

Hello everyone,
Last year I bought a green Elan S3 DHC that had recently been repatriated to the UK.
I have finally started to get a few jobs done. There are quite a few to do.....
It had a Sprinalux steering wheel installed and the horn had been moved to a toggle switch on a panel where the radio would be.
The horns work fine from the switch; they are live with the ignition off which I think is correct.
I bought a nice new Momo Heritage steering wheel and boss and have installed them.
However, I wanted to get the horn back to its rightful position.
I have soured the cable back from the dashboard switch and have identified the connector on the drivers side under dash. It is th correct colour as the wiring diagram. I bought a new horn push slip ring as the old one was missing and have also installed that, connecting it to the terminal under the dash and removing the link to the toggle switch. The Momo horn push/boss has two wires. One connects from a spring push that connects to the slip ring and that goes to the underside of the horn push. There is then an earth wire that goes back to the boss which would earth directly with the steering column.
Sadly the horn doesn't work. If I connect the earth lead to the earth switch on the original horn switch then the horn will 'toot' nicely, with the live coming through the new wire/slip-ring. The wires that earth the steering column to the chassis are in place.
When I use a volt meter, i get 12 v from the wire under the dash and from the terminal on the slip ring, when earthed.
Interestingly the metal casing on the outside of the steering column surrounding the indicator stalks etc seems to be earthed as I get 12 v when I connect the earth of the horn push to that. However, this doesn't power the horn. The horn push is new and works fine because all is well when I connect it to the wires going to the old toggle switch.
I am quite flummoxed by all of this.
Any ideas would be most appreciated :)
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PostPost by: Craven » Sat Nov 19, 2022 8:50 pm

Often these type of problems are because the steering wheel or hub are of anodised aluminium, anodise is an insulating medium so you need a earth path from the horn push through the wheel to earth.
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PostPost by: LaikaTheDog » Sun Nov 20, 2022 12:44 pm

Is the earth wire present that crosses the rubber donut just above the steering rack ?
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