Steve17
Member Since: 08 May 2016
Location: Essex
Posts: 422
  
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Is the discovery 3 a negative ground vehicle also is the horn live but then makes the sound when it is earthed by pressing the horn or is it earthed then made live when the horn is pressed cheers
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 9th Feb 2019 9:40 pm |
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TigerRecovery
Member Since: 31 May 2017
Location: Long Stratton, Norwich, Norfolk
Posts: 901
  
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I don't know of any vehicle built since the 70's that's positive earth, the last one I remember seeing was an FSO Serena from Poland on Wheeler Dealers. So yes your vehicle is negative earth.
For the horn circuit you need to look at the circuit diagram for your car to determine whether it's a switched 12V or switched ground. It's easy to check, how many wires are going to it? If it's 1, it's a switched supply, if it's 2 it could be a switched ground or supply.
Using a Voltmeter you can check for 12V on one wire before the horn is activated, if there's nothing then it's switched 12v, if there's 12V on one wire, it's a switched ground. 1972 Range Rover Classic 2 door V8
2013 Land Rover Discovery 4 HSE - SCRAPPED
2016 Land Rover Discovery 4 Landmark
2022 Volvo XC40 T5 PHEV 282HP FWD 3 cylinder!
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| 9th Feb 2019 9:43 pm |
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Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10667
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I would guess live when pressed.
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| 9th Feb 2019 10:58 pm |
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Globetrotter448
Member Since: 21 Mar 2017
Location: Londonderry NSW
Posts: 1812
 
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The horns are grounded and are supplied a voltage when pressing the horn button. The horn button supplies a ground to a relay. The relay switches the 12v through to the horn.
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| 10th Feb 2019 7:52 am |
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