Thread: Discovery 3 LED trailer lights

Hi guys,
Not sure about what has been covered in all 24 pages but ...
I believe d3 and d4s are the same sensing circuit for trailers. They will sense a trailer if the trailer blinkers give a load of about 10 ohms. In my d4 I have put load resistors across the trailer led lights and have no problems with the disco sensing the trailer.
By putting them at the back of the trailer (NOT IN THE CAR) you keep the inherent protection built into the disco in play. Otherwise you can't tell if you have forgotten to plug the trailer in, cable is broken, etc.

FYI, you don't need relays and I used 2x 18ohm 10watt resistors connected in parallel on each blinker. Connected from the blinker wire to ground (or just across each led light). 4 resistors in total ... about $2.00!!

It's all swings and round abouts... what happens when you want to tow another trailer that hasn't been modified? I chose to go for the module because my trailer is often used by a mate with an old hilux, he doesn't need the lights modified. I also wanted to be able to tow other trailers when the need arises (ie bringing home a load of bark for the garden using the trailer from the local garden centre).

If you've got $2 worth of resistors then I'd say yours are too low wattage. Given you are putting at least 12v to your resistors you would want a minimum of 8-10w resistors (assuming 18ohm). 50c each won't buy you resistors with that sort of power handling capability.

Originally Posted by CraigA

Hi guys,
Not sure about what has been covered in all 24 pages but ...
I believe d3 and d4s are the same sensing circuit for trailers.

No, the D3 isn't the same, and requires the relay approach.

Cheers,

Gordon

Originally Posted by gghaggis

No, the D3 isn't the same, and requires the relay approach.



Cheers,



Gordon

Yes it seems the engineers worked out the more efficient & less hassle some method of pulsing the light circuits on driver door close only - rather than continuously. Remove the need for the relay - relay is to prevent the twinkling - it doesn't change the "sensing"

Originally Posted by Meken

Yes it seems the engineers worked out the more efficient & less hassle some method of pulsing the light circuits on driver door close only - rather than continuously. Remove the need for the relay - relay is to prevent the twinkling - it doesn't change the "sensing"

We have just had issues with our Mercedes Actross prime mover getting a flat battery when parked for a few days.The cause,a broken wire in the trailer plug.The ECU kept looking for the trailer because it sensed side lights but no tail lights.Perhaps the drivers door switching the hunt for red october is a bloody good thing
Andrew

Originally Posted by BJM

It's all swings and round abouts... what happens when you want to tow another trailer that hasn't been modified? I chose to go for the module because my trailer is often used by a mate with an old hilux, he doesn't need the lights modified. I also wanted to be able to tow other trailers when the need arises (ie bringing home a load of bark for the garden using the trailer from the local garden centre).
If your LED light trailer has load resistors on it, it won't affect your mates car. If you use a "loaner", chances are they won't have LEDs and you won't have a problem.

If you've got $2 worth of resistors then I'd say yours are too low wattage. Given you are putting at least 12v to your resistors you would want a minimum of 8-10w resistors (assuming 18ohm). 50c each won't buy you resistors with that sort of power handling capability.

No, as I stated, they are 10W .. giving 20W of power handling from the parallel 18ohm resistors. They dissipate about 18Watts but its only for a short and intermittent time so should be reliable enough. Bolt them to a heatsink if you like. Yes, I paid about 50 cents each for them. Jaycar sells them for about $1.60.
Cheers

Does anyone know if the linear electronic design 'in car mount' can be installed with a Redarc Tow Pro system and if so, would it go before or after the brake controller?

cheers

I have both fitted to my 2014 Disco4. The TowPro was fitted by the dealer when we purchased the car and I fitted the Linear Electronics unit myself so I really have no idea which is before which....but, it shouldn't matter because they operate on different wires so shouldn't affect one another.