LED Adaptor Module

[Gravy]

I own a Linear Electronic Design LED Adaptor module which is configured for use with a Discovery 3. Is there differences in the trailer light functions between a Discovery 3 and 4 making this unit incompatible with my 2014 L319?

Did both models have trailer connection recognition which initiated sway control and transmission ratio changes?

[Tombie]

It’s different.

You can make one cheap and sell the one you have.

[Gravy]

It’s different.

You can make one cheap and sell the one you have.

Thankyou you have confirmed information I had been told. Do you have a circuit diagram to facilitate making your own? I prefer not to fit dummy load resistors.

[josh.huber]

Thankyou you have confirmed information I had been told. Do you have a circuit diagram to facilitate making your own? I prefer not to fit dummy load resistors.

Hey gravy,
you'll need to fit dummy load resistors or light bulbs. Most of us in here have dummy resistors fitted to a switch in the rear compartment. I simply open the till box and flick a switch when I hook up. I'll see if I can find the thread on the subject. The secret of using resistors it to let them hang in the breeze and don't tie them to your wiring. That way they don't melt anything.

[josh.huber]

Discovery 4 LED trailer lights
Discovery 4 LED trailer lights (https://www.aulro.com/afvb/l319-discovery-3-and-4-a/282788-discovery-4-led-trailer-lights.html)

[Tankmat]

Thankyou you have confirmed information I had been told. Do you have a circuit diagram to facilitate making your own? I prefer not to fit dummy load resistors.


There’s a circuit diagram here, post #18

LED trailers
LED trailers (https://www.aulro.com/afvb/l319-discovery-3-and-4-a/272077-led-trailers.html)

[Gravy]

There’s a circuit diagram here, post #18

LED trailers
LED trailers (https://www.aulro.com/afvb/l319-discovery-3-and-4-a/272077-led-trailers.html)

This issue on the Discovery 4 is not as complex as I first assumed. My experience with my Volvo XC60 made me believe the installing dummy load resistors would not resolve the problem.

The Disco 4 obviously possess some enhancements that connection of a trailer with LEDS does not cause blown globe diagnostics and reversing sensors to malfunction.

Dummy load resistors do have some disadvantages in that large amounts of energy have to be dissipated when they are energised. Having to only install them in the indicator circuits is a bonus because energisation times are short, however should you have to activate your Hazard Lights for an extended period there could be a problem if the resistors are not installed on a heat sink.

I am still of two minds the Linear Electronics Design module to address the issue is expensive compared to fitting dummy load resistors.

If my brain was sharper I am sure an electronic circuit could be devised to mimic this function, I thought a D4 owner may have already done this.

Appreciate your advice.

[kelvo]

I am still of two minds the Linear Electronics Design module to address the issue is expensive compared to fitting dummy load resistors.

Appreciate your advice.
Three guess what’s inside a Linear Electronics Design module…

[Gravy]

Three guess what’s inside a Linear Electronics Design module…

Have you dismantled one? Tomorrow I will do so as I want to establish whether I can convert the D3 module for use with the D4.

[kelvo]

Have you dismantled one? Tomorrow I will do so as I want to establish whether I can convert the D3 module for use with the D4.
No I haven’t.
But I’ll guess the D3 module has two relays and two load resistors in it.
The D3 module will also work on a D4.
I will also guess that if the D3 & D4 modules cost the same they will be the same, if the D4 is cheaper then it will only have two load resistors.

The benefit of the L.E.D. module is it’s all mounted in an aluminium box (Heatsink).

I was able to get a suitable finned aluminium heatsink to mount my two load resistors on and then have a switch to enable or disable LED trailer towing.

[Tombie]

Have you dismantled one? Tomorrow I will do so as I want to establish whether I can convert the D3 module for use with the D4.

You may struggle there. The insides are potted.

On a D3 it’s a circuit board with board mounted relays and resistors.

On a D4 it’s sans relays.

[superhet]

Companies that make these devices over complicate the solution.
I built a box on the A frame of my caravan and put high wattage resistors across the tail, stop and blinker wires. I used resistor values that are equal to the resistance of the incandescent globes. ie 10W tail lamp ~ 15ohms. 21W Stop/Blinker ~ 7ohms. So for the tail lamp 16ohms 10W and for the others 8ohms 25W will do. If you get the proper power resistors you won't need a heatsink.

[kelvo]

Companies that make these devices over complicate the solution.
I built a box on the A frame of my caravan and put high wattage resistors across the tail, stop and blinker wires. I used resistor values that are equal to the resistance of the incandescent globes. ie 10W tail lamp ~ 15ohms. 21W Stop/Blinker ~ 7ohms. So for the tail lamp 16ohms 10W and for the others 8ohms 25W will do. If you get the proper power resistors you won't need a heatsink.
You over complicated the solution for a D4.
At the minimum you only need to put a resistor on one of the indicator circuits, the D4 will recognise that a trailer is attached but you’ll only get the trailer icon flashing on the dash when you use the indicator with the resistor attached.
For symmetry you fit a resistor to both indicator circuits.

[Tedio]

I put a resistor in the right indicator circuit in my round to flat adapter. Riveted it to the adapter, no heat sink. Works fine.

[RHS58]

I went with the LED adapter on my 2013 D4 way back in 2013.
Yes, I probably paid more than I needed to or should have, but wth, it works fine with the flick of a switch.
Went with what I thought was best and easiest at the time. Have had no issues so am happy.

[Gravy]

Thanks for the heads up I did not attempt to dissolve the potting compound. I measured the resistance values between the indicator connections (green and yellow) and ground and came up with values of 7.1 ohms. Terminated all other incoming and outgoing connections except the incoming green, yellow and white wires on the module and connected the wires in parallel into the trailer wiring harness. This resulted in the dash displaying the trailer symbol if either indicator direction or the Hazard Lights were selected.

To automate the switching of the module I connected a 12V lighting relay into the earthing wiring of of the module. I use the NC contacts on the relay, connected the NC reed switch on the Narva Trailer Socket to the coil powered from an ignition switched 12V supply.

This process means that the module resistors are only connected to ground when the socket reed switch is opened by connection of the trailer plug. Only disadvantage with this system is that the switching relay is continually energised whilst there is no trailer plug in the socket, I will evaluate if I can reverse the switching logic.

[Discodicky]

I went with the LED adapter on my 2013 D4 way back in 2013.
Yes, I probably paid more than I needed to or should have, but wth, it works fine with the flick of a switch.
Went with what I thought was best and easiest at the time. Have had no issues so am happy.

Same.
I purchased one and it works fine, placed in LHR pocket near vehicle jack.
The owner of LED actually owned a nice looking black D4 HSE.
Being fundamentally lazy, I leave my switch "on" all the time and simply watch the Trailer Light on the dash flash when ever I use indicators with or without a trailer coupled.

[DieselLSE]

Being fundamentally lazy, I leave my switch "on" all the time and simply watch the Trailer Light on the dash flash when ever I use indicators with or without a trailer coupled.
Probably not a good idea as the car assumes there is a trailer and adjusts all sorts of settings to allow for it.

[Discodicky]

Probably not a good idea as the car assumes there is a trailer and adjusts all sorts of settings to allow for it.

That's interesting!
It hadn't occurred to me that it would be the case. I assumed it would only make adjustments to settings when I connected the trailer electrical coupling.
Many thanks for that!

[Tombie]

That's interesting!
It hadn't occurred to me that it would be the case. I assumed it would only make adjustments to settings when I connected the trailer electrical coupling.
Many thanks for that!

That’s exactly what the resistors are there to do…
Make the vehicle think there’s a load on the trailer plug.

[DiscoJeffster]

I’m might be getting old and grumpy but I feel this thread needs a head slap emoji [emoji1787]
I mean, what was the point of the car detecting the trailer if there was no point to it?

[Celtoid]

Probably not a good idea as the car assumes there is a trailer and adjusts all sorts of settings to allow for it.

My Linear box also gets quite toasty when operating. I'm not sure how much of an issue that is, but when I use it I try to avoid leaving the blinkers running for too long (like hazard lights).

[Tombie]

My Linear box also gets quite toasty when operating. I'm not sure how much of an issue that is, but when I use it I try to avoid leaving the blinkers running for too long (like hazard lights).

Toasty as in can’t keep hand touching or ?

[superhet]

I’m might be getting old and grumpy but I feel this thread needs a head slap emoji [emoji1787]
I mean, what was the point of the car detecting the trailer if there was no point to it?

Agree. On most LR's it adjusts the traction controls, turns off the rear parking sensors and possible other stuff. On my FL2... just the parking sensors .

[superhet]

You over complicated the solution for a D4.
At the minimum you only need to put a resistor on one of the indicator circuits, the D4 will recognise that a trailer is attached but you’ll only get the trailer icon flashing on the dash when you use the indicator with the resistor attached.
For symmetry you fit a resistor to both indicator circuits.

kelvo you may be correct. I did all lights so it did not mess with the blown bulb diagnostics.

[Celtoid]

Toasty as in can’t keep hand touching or ?

I haven't tried to see how hot it will get Tombie. I can hold the box but it's getting to the north side of warm relatively quickly. That could be the heat sink just doing it's thing and dumping the resistor generated heat and it may not get any hotter though.

Cheers,

Kev.

[Tombie]

I haven't tried to see how hot it will get Tombie. I can hold the box but it's getting to the north side of warm relatively quickly. That could be the heat sink just doing it's thing and dumping the resistor generated heat and it may not get any hotter though.

Cheers,

Kev.

Thanks Kev

In testing mine I could maintain holding it.
It got uncomfortable after about 7-8 minutes, still wasn’t ‘melt anything or catch fire to something’ hot though.

Mine are built using a cast ally box and the resistors mounted with thermal epoxy.