Discovery 3 LED trailer lights

**harlie** · 28th June 2011, 09:21 AM

If you have a D3 then the diagram Colin posted in post #16 is more suited than mine for the L322 RR.

Just to add to it – for installation in the van/trailer;
Green OR Yellow wire from plug goes to pin 30 AND pin 85 on relay.
Earth (white) goes to pin 86 on relay.
Green OR Yellow wire going to tail lights goes on Pin 87 on relay
Resistor crosses between Pins 85 and 86.

You can install this in the car, it would mean that 1 box could be used for multiple trailers, but it would need a switch (or the car will think it has a trailer all the time) and you loose the testing function for the trailer lights – with the box on the trailer it is still testing the plugs, and if you change the output to pin 87a from 87 (change over relay only) it will still test the light itself…

dubv · 2nd December 2011, 08:11 PM

Originally Posted by djhampson

I made a box up with 2 relays. The pulse to check the lights isn't enough to operate the relays. A switch means I can bypass my circuit and use non-LED trailer lights as per normal.

When my circuit is enabled the trailer detection light comes on so I assume the car knows that there is a trailer attached.

I have made an in-line system between my vw and the trailer which uses resistors (one each in parallel with each of the blinkers, tail and stop lights) which works fine. It has a male plug on one end and female on the other and it connects bewteen the car and any trailer. The four resistors are screwed onto a short piece of aluminium pipe which is the common earth. Looks a bit like a bomb. If I hook up a trailer with incandescent lights i don't connect the extra load.
Can you explain why you need the relays?

**djhampson** · 2nd December 2011, 08:48 PM

Originally Posted by dubv

I have made an in-line system between my vw and the trailer which uses resistors (one each in parallel with each of the blinkers, tail and stop lights) which works fine. It has a male plug on one end and female on the other and it connects bewteen the car and any trailer. The four resistors are screwed onto a short piece of aluminium pipe which is the common earth. Looks a bit like a bomb. If I hook up a trailer with incandescent lights i don't connect the extra load.
Can you explain why you need the relays?

I didn't need the relays... I just had them available and didn't have any resistors. And I didn't think to use resistors

dubv · 3rd December 2011, 07:59 AM

Originally Posted by djhampson

I didn't need the relays... I just had them available and didn't have any resistors. And I didn't think to use resistors

Thanks. More ways of killing a kat...

**LGM** · 3rd December 2011, 08:42 AM

Read some posts last year re the LED trailer lights issue.

When I picked up my D4 (Sep11) and got home I hooked up to my trailers and caravan all fitted with LED lights. The trailer and caravan lights operated and did not pulse (I guess LR fixed that bit of the problem) but the car did not recognise the trailer or van was attached. This was a pain in the butt as the park sensors would squawk, no trailer indication on the dash and I don't think the trailer assist program would operate (not that I could tell).

A search of the web indicated that the problem with LED's was not unique to LR's but to most european makes. Anyhow I tracked down a crowd from Melbourne called Linear Electronic Design who make a little 'gizmo' that hooks into the car wiring and can be switched on / off depending on what lighting is fitted to the item you are towing. I purchased the system (a small alloy box and wires with a switch) $265 delivered.

www

Yep, not cheap, but I only need the one system to cater for all my towed kit and given that someone has put in the time and effort they need to make a return and besides my electrical capability is 'limited'!

The system was easy to install and it works a treat. It allows me to tow whatever I need with no fuss and all systems working. All I have to do is turn it on if the towed item is equipped with LED lighting. The car then recognises that a 'trailer' is attached the indicator on the dash operates, the park sensors deactivate and (I assume) the trailer assist program is working. All that is visable inside the car near the rear tailgate is a small rocker switch.

dubv · 4th December 2011, 05:44 AM

sorry double post. haven't quite got the idea of deleting

Alan43 · 15th January 2012, 12:36 PM

Originally Posted by tochse

Can you send me a copy of the circuit you used to make your own LED Adaptor

Could you please supply a circuit for the LED adaptor for my use?

Alan43 · 15th January 2012, 12:41 PM

Are you able to give me contact details for linear electronics as I cannot find them with google.
Alan43 Brisbane

**sniegy** · 15th January 2012, 12:47 PM

Alan, this is the gents website & contact email address, i also have one in my D4 fitted, it is a great unit.

Cheers.

www

**bbyer** · 15th January 2012, 01:15 PM

Originally Posted by Alan43

Could you please supply a circuit for the LED adaptor for my use?

I used the wiring drawing in post #16 of this thread to make up a LED adapter box for the NAS 7 blade round plug we use here.

It works OK, (green trailer light on dash flashes properly as well), but I decided that one would be probably better to purchase an adapter already built. As below, mine is kind of heavy, bulky, and it was more than a few pennies to purchase the parts. I used a pair of 6 ohm 50 watt aluminum cased resistors and for the can, a near explosion proof duplex box to provide a weather resistant heat sink - they are heavy however.

I also decided while the Hella relays I purchased appear to work OK, that I probably should have purchased relays with internal anti-spiking resistors.

I note that our air compressor relay R7 has a built in 560 ohm resistor mounted internally across the relay coil to soak up voltage spikes when the relay opens. The purpose of the anti-spike resistor is to protect vehicle circuits from voltage spikes due to the make and break of the relay. I kind of think this was not Land Rover overkill but necessary; hence probably the signal light adapter should use that design of relay as well.

I presume that the pre built ones have that sort of concern under control.

Thread: Discovery 3 LED trailer lights

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LED Trailer light fix

Made LED adaptor box for my LR3.

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