Discovery 2017

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  • MAC OSX
    Member Since: 08 Dec 2016
    Location: Newry
    Posts: 52
    United Kingdom 
    2017 Discovery TDV6 HSE Lux Indus Silver

    Trailer Trafficator indicator.

    When towing a trailer fitted with LED lamps the (Green Trailor symbol) Trafficator Indicator does not work (works with trailer fitted with 21W lamps). I believe this indicator is a legal requirement.
    Anyone got any idea as to the value of resistor required (between lead and earth to operate indicator lamp).
    9th Oct 2018 1:03 pm
  • B50int
    Member Since: 02 Sep 2018
    Location: Yorkshire
    Posts: 158
    United Kingdom 

    You can fit a resistor in parallel with the trailer LED indicator to make the dashboard indicator function, but then the indicator is proving only the cables and resistor, not the LED. So be aware, It means the LED could fail and you would still get the resistor proving to the car that the lights were functioning even though they were not!

    How you work it out
    Power=volts x amps so a 21watt filament at 12v draws 21/12=1.75amps

    The equivalent load that this presents is found with ohms law volts=current x restistance
    Therefore a resistor of 12/1.75 = 6.85ohms

    You will need to get a wire wound resistor rated greater than 21 watts. Even then expect it to get quite warm when in use! You will need one resistor for each indicator circuit.

    Jon
    9th Oct 2018 3:31 pm
  • IndusD4
    Member Since: 28 Jan 2018
    Location: Sydney
    Posts: 698
    Australia 

    For the D4 I used a 50w 6 ohm resistor on one of the indicator circuits. Your D5 must be 2017 model as my 2018 works correctly with LED trailer lights without the need for a resistor.

    Ron
    2016 D4 TDV6
    IIDTool BT
    9th Oct 2018 6:20 pm
  • B50int
    Member Since: 02 Sep 2018
    Location: Yorkshire
    Posts: 158
    United Kingdom 

    I wonder if it might be model year specific.

    My MY18 with factory fit towbar and electrics also works fine with my Sterling Eccles that has LED lights.

    Jon
    9th Oct 2018 7:19 pm
  • MAC OSX
    Member Since: 08 Dec 2016
    Location: Newry
    Posts: 52
    United Kingdom 
    2017 Discovery TDV6 HSE Lux Indus Silver

    Many Thanks for your replies.

    The same calc as I did.
    Point about resistor only proving wiring not the LED unit itself very true.
    Since this does not apply to later versions than my 2017 it MIGHT be SOFTWARE related.
    9th Oct 2018 10:39 pm
  • Road Runner 2017
    Member Since: 14 Jan 2017
    Location: Scotland
    Posts: 2010
    Scotland 
    2018 Discovery Si6 HSE Lux Santorini Black

    Fitted new Led lightboard to the trailer last weekend and the green indicator works on the dash. Like you chaps are saying, it's probably software related or MY related.
    MY17 First Edition - 3L Diesel Td6 - Farallon Black - Roof rails,side steps,tints,tow bar,mudflaps,door strips.
    MY18 Hse Luxury - 3L Petrol Si6 Supercharged - Santorini Black - Roof rails,side steps,tints,tow bar,mudflaps,door strips,22's,dynamic pack 1,bonnet vents,t.v,dual view,frontcooler,360°camera,rear cooler/warmer,roof vane,black LR badges,wade sensing,door sill plates,boot liner, solar screen,wind deflectors,service plan,tracker,speed camera detector,dual dash cameras,ceramic coating.
    9th Oct 2018 10:56 pm
  • greg-g
    Member Since: 28 Aug 2018
    Location: Tasmania Australia
    Posts: 17
    Australia 
    2017 Discovery Sd4 (240) SE Corris Grey

    I had to fit load resistors to my MY17.
    I used 6 ohm 100w resistors in the signal and brake circuits.
    I just made a box that the trailer cable plugs into, and it then plugs into the car plug.
    100w is overkill but they are cheap on ebay
    MY19 D5 SD4 SE
    11th Oct 2018 11:22 am
  • IndusD4
    Member Since: 28 Jan 2018
    Location: Sydney
    Posts: 698
    Australia 

    Not overkill but they won't get as hot as 21W or 50W resistors.
    2016 D4 TDV6
    IIDTool BT
    11th Oct 2018 5:52 pm
  • MalithS
    Member Since: 16 Aug 2018
    Location: Warwickshire
    Posts: 140
    United Kingdom 
    2019 Discovery Td6 HSE Santorini Black

    B50int wrote:
    I wonder if it might be model year specific.

    My MY18 with factory fit towbar and electrics also works fine with my Sterling Eccles that has LED lights.

    Jon


    All Disco 5 need atleast 1.75A (21W) on the direction indicators for the vehicle to 'detect' that the lamp is operating. So by using the resistor you are drawing that current to fool the vehicle into thinking there is a trailer fitted.

    If the vehicle doesnt detect this load it doest setup other functions (i.e rear PDC disable / trailer stability control) on the car correctly for towing.
    15th Oct 2018 11:35 am
  • B50int
    Member Since: 02 Sep 2018
    Location: Yorkshire
    Posts: 158
    United Kingdom 

    My MY18 knows it’s there. Dashboard tell tale flashes nicely in sync with the led indicators on the caravan and the PDC turns off as it should. No resistors.

    Jon
    15th Oct 2018 3:39 pm
  • AndrewS
    Member Since: 28 Apr 2016
    Location: Pembridge
    Posts: 410
    United Kingdom 
    2019 Discovery SDV6 HSE Silicon Silver

    My 17 my works fine with LED on the trailer
    15th Oct 2018 3:46 pm
  • IndusD4
    Member Since: 28 Jan 2018
    Location: Sydney
    Posts: 698
    Australia 

    MalithS wrote:
    All Disco 5 need atleast 1.75A (21W) on the direction indicators for the vehicle to 'detect' that the lamp is operating. .


    That's not true, numerous reports from cars that are working perfectly without (including mine), I would have said all 2017 models but Andrew proved that wrong as well. I'm inclined to believe it might be a software update now.

    Ron
    2016 D4 TDV6
    IIDTool BT
    15th Oct 2018 6:22 pm
  • jimbg
    Member Since: 23 Jun 2016
    Location: Devon
    Posts: 1472
    United Kingdom 

    Was there not something on Topix about this?
    15th Oct 2018 8:39 pm
  • greg-g
    Member Since: 28 Aug 2018
    Location: Tasmania Australia
    Posts: 17
    Australia 
    2017 Discovery Sd4 (240) SE Corris Grey

    The MY19 online manual still talks about the need for load resistors.
    MY19 D5 SD4 SE
    15th Oct 2018 10:00 pm
  • MalithS
    Member Since: 16 Aug 2018
    Location: Warwickshire
    Posts: 140
    United Kingdom 
    2019 Discovery Td6 HSE Santorini Black

    IndusD4 wrote:
    MalithS wrote:
    All Disco 5 need atleast 1.75A (21W) on the direction indicators for the vehicle to 'detect' that the lamp is operating. .


    That's not true, numerous reports from cars that are working perfectly without (including mine), I would have said all 2017 models but Andrew proved that wrong as well. I'm inclined to believe it might be a software update now.

    Ron


    Hi,

    Its actually stated in the owners hand book here:



    Nothing has changed to this detection threshold since the start of D5. If your LED lamps work with the car it just means that you have a lamp that is drawing atleast 1.75A current draw. The detection has nothing to do with LED lights, its just that most LED tend to draw far less current than a normal incandescent bulb so more chances of it being less than 1.7A draw.
    15th Oct 2018 10:55 pm
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