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| LandymanStefan Member Since: 30 Aug 2017 Location: Surrey Posts: 881   
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I currently have an uproar 4x4 worklight on the back of my car with two switched ground wires coming off it. One in the boot so i can turn it on and off from there and one to the dash with a switch.
I want to add a second light with the same setup but dont want to run a second wire to the dash, everything from the first light is nice and neat and id reather not run a twin cable down (but will if i have to) Ideally i want to share the ground that runs to the dash for both lights and then individual swithes for each light in the boot. Only problem i could see if i did that is both lights would turn on regarless of what switch was turned on in the boot am i correct in thinking i can isolate each light would be with a diode? 2 of these https://www.ebay.co.uk/itm/Durite-0-834-10...SwCuBcc6oP I drew a picture pretending i know anything about electronics... Would this work?  Click image to enlarge |
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5th Mar 2021 9:02am |
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| LandRoverAnorak Member Since: 17 Jul 2011 Location: Surrey Posts: 11324 
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That won't work I'm afraid - you'll still turn both lights on. How would the dash switch 'know' which light you're trying to turn on?
The only way to use a single switch to turn on two independent things is if it has two pathways within it, i.e. an ON-OFF-ON changeover switch, or perhaps a rotary switch Darren 110 USW BUILD THREAD - EXPEDITION TRAILER - 200tdi 90 BUILD THREAD - SANKEY TRAILER - IG@landroveranorak "You came in that thing? You're braver than I thought!" - Princess Leia |
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5th Mar 2021 9:55am |
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| LandymanStefan Member Since: 30 Aug 2017 Location: Surrey Posts: 881
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Ah I didn’t make myself clear. I want the switch on the dash to turn on both lights together. Then the two switches in the boot to switch the light individually.
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5th Mar 2021 11:59am |
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| rallysteve Member Since: 10 Feb 2014 Location: Cumbria Posts: 2238 
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Think the OP is saying that he is happy with the dash switch operating both lights but wants them individually switchable in the boot. If so, i would recommend just using two-way switches in the boot for each lamp rather than diodes which will get hot and also drop upto 1v over each:
Click image to enlarge Steve 02' 110 TD5 Double Cab Rebuild Thread |
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5th Mar 2021 12:00pm |
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| LandRoverAnorak Member Since: 17 Jul 2011 Location: Surrey Posts: 11324
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Ah! I see what you mean now. Steve's solution is ideal
 Darren
110 USW BUILD THREAD - EXPEDITION TRAILER - 200tdi 90 BUILD THREAD - SANKEY TRAILER - IG@landroveranorak "You came in that thing? You're braver than I thought!" - Princess Leia |
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5th Mar 2021 12:05pm |
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| custom90 Member Since: 21 Jan 2010 Location: South West, England. Posts: 20580
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I would prefer switches too, the only practical solution I’ve used Diodes for is in the live line on HD relays coils to prevent fly back voltage upstream back to sensitive power supplies.
Although very very small there is some voltage leakage and as mentioned voltage drop as well. KEEP CALM AND Drill ON 🇬🇧🏴🏴🏴🇮🇪🇺🇸⛽️🛢️⚙️🧰💪 |
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5th Mar 2021 12:43pm |
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| rallysteve Member Since: 10 Feb 2014 Location: Cumbria Posts: 2238
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I have used diodes a few times but they should only really be used for creating 'logic' functions with very low power draw circuits (e.g. relay triggering).
I have used them: - On old car alarm installations to isolate Left and Right hand indicators when the alarm only provides a single output (although this is a higher power use, it is only short duration and flashing), - To create a single positive feed from both of my batteries which allows the contactor which connects them together to be closed if either of the batteries is not present or totally flat, - In a 2 speed cooling fan circuit which changes two fans from series to parallel to vary the speed. Steve 02' 110 TD5 Double Cab Rebuild Thread |
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5th Mar 2021 1:06pm |
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| LandymanStefan Member Since: 30 Aug 2017 Location: Surrey Posts: 881
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Looks like a neat solution Steve
Great idea |
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5th Mar 2021 1:18pm |
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| LandymanStefan Member Since: 30 Aug 2017 Location: Surrey Posts: 881
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All good folks
Click image to enlarge |
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13th Mar 2021 1:34pm |
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