D4 not detecting trailer wiring

[wombathole]

Just replaced the camper's tail lights with LED units and new cabling up to the car. All the lights are working as expected, but the D4 is not detecting the trailer connection any more. (ie: no trailer icon on the driver's display)

I'm assuming the D4 is therefore not going to use the trailer assist driving mode. :(

Any idea why its not being detected? impedance of LEDs compared to bulbs?

And how do i fix it?

Thanks, Andy

[cripesamighty]

"impedance of LEDs compared to bulbs"

Yep, this is common. Wire in a globe between the earth wire and one of the indicator circuits as a cheap fix (on the trailer or the plug itself is fine).

I think Gordon's (gghaggis) GOE off-road booklet covers it somewhere but I don't have it on me to check. I'm sure someone will be along shortly with more detailed info.

[sniegy]

Has been covered many many times before.
Search the forum.
But in Short you will need one of these.
Linear Electronic Design | Home (http://www.linearelectronicdesign.com)
Or as has others done make your own.

Cheers

[nat_89]

Ive only towed a trailer once or twice with mine thats all and never noticed anything about a trailers on the screen. Is it meant to show a icon or something when towing?

[sniegy]

Ive only towed a trailer once or twice with mine thats all and never noticed anything about a trailers on the screen. Is it meant to show a icon or something when towing?

When you indicate the trailer icon illuminates in the instrument pack to let you know you have a working indicator.

[nat_89]

When you indicate the trailer icon illuminates in the instrument pack to let you know you have a working indicator.

Cheers never knew ill keep an eye out for it!!

[Lotz-A-Landies]

If you don't have the resistor pack in the trailer wiring when using LEDs, following drivers may notice your blinker lamps constantly flickering.

You can get a pack from Ford dealers as the Territory has the same problem and the pack is relatively cheap when compared to other after-market ones.

Diana

[Mossy]

I just bought a Narva resistor and wired it across the r/h indicator.
The car now recognises there is a trailer, though the trailer light on the dash only flashes with the r/h indicator.
You would have to add another resistor to the l/h indicator if you wanted that to flash on the dash as well.

Cheers Mossy

[jwb300]

If you don't have the resistor pack in the trailer wiring when using LEDs, following drivers may notice your blinker lamps constantly flickering.

You can get a pack from Ford dealers as the Territory has the same problem and the pack is relatively cheap when compared to other after-market ones.

Diana

Diana,

Does this allow all of the D4 towing functions to work properly? I assume it fits into the LR round plug too?

Cheers,
JWB300

[jwb300]

I just bought a Narva resistor and wired it across the r/h indicator.
The car now recognises there is a trailer, though the trailer light on the dash only flashes with the r/h indicator.
You would have to add another resistor to the l/h indicator if you wanted that to flash on the dash as well.

Cheers Mossy

That is exactly what I have done but I'm not sure if doing this enables all of the towing functions?

Surely someone has invented an adaptor that contains two resistors so that you don't have to install resistors on all of your trailers.

Cheers,
JWB300

[101RRS]

Surely someone has invented an adaptor that contains two resistors so that you don't have to install resistors on all of your trailers.

Cheers,
JWB300

Yes they have - ebay is full of them and there must be about 100 threads on this forum on the issue. Here is but one example on ebay LED Trailer Module Land Rover Discovery 3 4 Range Rover Sport Landrover in Beaumaris, VIC | eBay (http://www.ebay.com.au/itm/LED-trailer-module-Land-Rover-Discovery-3-4-Range-Rover-Sport-Landrover-/181624715936?pt=Caravan_Parts_Accessories&hash=item2a49ad3aa0)

I just made my own from information on this forum. I chose to make it a box that plugs in between the trailer connector on the car and the connector on the trailer. I could have hard wired it into the car between the car wiring and the car's trailer plug.

Garry

[jwb300]

Yes they have - ebay is full of them and there must be about 100 threads on this forum on the issue. Here is but one example on ebay LED Trailer Module Land Rover Discovery 3 4 Range Rover Sport Landrover in Beaumaris, VIC | eBay (http://www.ebay.com.au/itm/LED-trailer-module-Land-Rover-Discovery-3-4-Range-Rover-Sport-Landrover-/181624715936?pt=Caravan_Parts_Accessories&hash=item2a49ad3aa0)

I just made my own from information on this forum. I chose to make it a box that plugs in between the trailer connector on the car and the connector on the trailer. I could have hard wired it into the car between the car wiring and the car's trailer plug.

Garry

Thanks Garry,

I have done a fair bit of reading on this forum but what I really want is a nice small module that could probably be built into a standard plug adaptor. Something like the Ford Ranger ones:

NEW Genuine Ford PX Ranger LW MK2 Focus 12pin LED Resistor Loom Trailer Adaptor | eBay (http://www.ebay.com.au/itm/NEW-GENUINE-FORD-PX-RANGER-LW-MK2-FOCUS-12PIN-LED-RESISTOR-LOOM-TRAILER-ADAPTOR-/231196025364?pt=AU_Car_Parts_Accessories&hash=item35d45b6214)

Those box style ones that you linked to are ridiculous. I don't want that thing hanging off my trailers. You would basically have to cable tie the damn thing to every different trailer you used with LED lights.

JWB300

[101RRS]

Double sided velcro ties work great.

I don't think you will find what you are looking for.

Why not hard wire the LR one into your car before your plug and you can just plug in any trailer without issue.

Good luck with it

Garry

[Meken]

Double sided velcro ties work great.

I don't think you will find what you are looking for.

Why not hard wire the LR one into your car before your plug and you can just plug in any trailer without issue.

Good luck with it

Garry


If he hard wires it into car it will make the car think there is a trailer connected all the time

[discotwinturbo]

If he hard wires it into car it will make the car think there is a trailer connected all the time

The modules comes with a switch to turn on and off as needed.

Brett....

[101RRS]

The modules comes with a switch to turn on and off as needed.

Brett....

Thankyou

[Meken]

Oh yes if it's a linear elec in car module they do - the way I read the post it seemed it was suggested to hardwire in one of the inline trailer types into the car

[simmo1]

Folks,

Bought a s/h caravan with led rear lights. Wired up a 21w globe to the right hand indicator circuit. Car recognises the van as the little man on the dash appears when using the RH indicator BUT the reversing beepers and camera are still in full function.

Would anyone have any clue as what isn't happening here or what to do?

Cheers, Simmo

[gghaggis]

With the engine off, try opening & closing the driver door to re-latch the circuit.

Cheers,

Gordon

[simmo1]

Thanks Gordon. I reckon I have tried most things whether by intention or accident. It's currently off the car, will try again tomoz.

Cheers Simmo

[Peteren]

Just a note on the resistor units from FoMoCo, they don't work on a D4.
Ordered one and tried it, no luck.
Opened it up and found the resistors are 120 Ohms, nowhere near enough load for the D4 to detect a trailer connected.


Got a couple of Narva 21 watt resistors and rebuilt the adapter, it now works fine


https://www.aulro.com/afvb/images/imported/2015/01/655.jpg

[Theoldies]

That is exactly what I have done but I'm not sure if doing this enables all of the towing functions?

Surely someone has invented an adaptor that contains two resistors so that you don't have to install resistors on all of your trailers.

Cheers,
JWB300



I used two Narva LED resistors and made my own adaptor. Plugs into D4, resistor box sits on trailer, the trailer plug plugs into adaptor. Works a treat. https://www.aulro.com/afvb/images/imported/2016/06/138.jpghttps://www.aulro.com/afvb/images/imported/2015/12/13.jpg

[Boggs]

I recall seeing a post here that said the problem was not an issue on a 14MY or later. I can't find it.
I'm ordering a new boat trailer and would consider requesting the manufacturer not put the standard LED lights on it if it is going to cause hassles. Frankly I can't see any advantage of LEDs on a trailer of any sort. I doubt power savings would be an issue as you would generally have the engine running with the lights on.

[ScottD4]

I recall seeing a post here that said the problem was not an issue on a 14MY or later. I can't find it.
I'm ordering a new boat trailer and would consider requesting the manufacturer not put the standard LED lights on it if it is going to cause hassles. Frankly I can't see any advantage of LEDs on a trailer of any sort. I doubt power savings would be an issue as you would generally have the engine running with the lights on.

Hey Boggs,

The way I understand it is the LED lights on your trailer won't pulse anymore (like they did previously), however the Discovery still won't know there is a trailer attached. So:

* Rear sensors will go off continuously when you have it in reverse (unless you switch them off which is done easily enough)
* Can't get to extended height
* Dash won't indicate there is a trailer attached when you indicate

I understood LED's to be longer lasting, as well as more friendly to water which might be beneficial in your case?

[Tombie]

Hey Boggs,

The way I understand it is the LED lights on your trailer won't pulse anymore (like they did previously), however the Discovery still won't know there is a trailer attached. So:

* Rear sensors will go off continuously when you have it in reverse (unless you switch them off which is done easily enough)
* Can't get to extended height
* Dash won't indicate there is a trailer attached when you indicate

I understood LED's to be longer lasting, as well as more friendly to water which might be beneficial in your case?

Still works - with a trailer fitted and detected it is not automatic requiring driver intervention.

[wbowner]

Hi,
I have a MY14 d4.

I got the internal module from electronic design (sorry forgot the name).
it comes with a switch to turn it on or off.

If I forget to turn it on I find both indicator lights in my van will flash at the same time when I use the indicator. A good way to remember to turn it on as I always check the lights after connecting the van, well mostly.

I must admit I did not notice the difference otherwise in towing but that is probably me.

Without the module the car did not recognize a trailer was connected. There was no green trailer displayed in the console when you flicked the indictor.

So yes the MY14 still has the problem but I believe a bit different from other years.

Richard

[Peteren]

I recall seeing a post here that said the problem was not an issue on a 14MY or later. I can't find it.
I'm ordering a new boat trailer and would consider requesting the manufacturer not put the standard LED lights on it if it is going to cause hassles. Frankly I can't see any advantage of LEDs on a trailer of any sort. I doubt power savings would be an issue as you would generally have the engine running with the lights on.


LED lights are not recognised by the D4, you will need to fit at least one resistor or fit incandescent indicators, have just gone through this with my MY15, see top of page

[dannog]

hi, I'd like to do the same but wondering did you simply wired the resisters in line with each of the indicators (ie cut the cable and soldered resister in) or did they have to cross to the earth?

[SBD4]

Across to earth. What you are describing is putting the resistor in series with the LED lights, they need to be in parallel.

[osborneparkautospark]

Please note resistors can run very hot. Please either insulate them accordingly or mount them to metal surfaces in areas where they can dissipate heat safely.

[discotwinturbo]

Across to earth. What you are describing is putting the resistor in series with the LED lights, they need to be in parallel.

I wonder who else did it that way before a fellow LR owner came to the rescue ?

:-) :-)

Brett...

[dannog]

Thanks for the clarification.

So that means for the Disco 4 I need 4 resisters. One on each of the indicators, brake and tail light. The box would need to be large enough to hold 4 resisters.

Given that's all that's in these magic boxes you can buy why do they cost $200 plus ?

[ScottD4]

Thanks for the clarification.

So that means for the Disco 4 I need 4 resisters. One on each of the indicators, brake and tail light. The box would need to be large enough to hold 4 resisters.

Given that's all that's in these magic boxes you can buy why do they cost $200 plus ?

Because people like me who have NO IDEA about vehicle electronics and general electrics for that matter wouldn't know how to wire one up.

If you're happy to put one together that works I'll pay you the money instead.

[BMKal]

Thanks for the clarification.

So that means for the Disco 4 I need 4 resisters. One on each of the indicators, brake and tail light. The box would need to be large enough to hold 4 resisters.

Given that's all that's in these magic boxes you can buy why do they cost $200 plus ?

You only need them on the indicators. ;)

You can get away with just a single resistor on one of the indicator circuits only. This is enough for the vehicle to sense that a trailer is connected, and will stop the reversing beepers continually going off when in reverse etc but it will only show the flashing trailer indicator on the dash for that same side indicator. To have the flashing indicator on the dash working for both side indicators, you need to put a resistor in both indicator circuits on the trailer.

[dannog]

Thanks guys I can hardly believe its that simple. 2 resisters on the trailer and its fixed. Cheers

[CBurgo]

Just a note on the resistor units from FoMoCo, they don't work on a D4.
Ordered one and tried it, no luck.
Opened it up and found the resistors are 120 Ohms, nowhere near enough load for the D4 to detect a trailer connected.


Got a couple of Narva 21 watt resistors and rebuilt the adapter, it now works fine


https://www.aulro.com/afvb/images/imported/2015/01/655.jpg

I just want to say a big thanks to Peteren (and the wider AULRO Community) for posting this photo solution to the D4 LED Caravan lighting issue.

(I was also amazed at how little information I could get from official LR outlets when making enquiries about a fix for what is sure to be a fairly widespread issue)

Anyhow, based on the photo above and information in this forum, I made my own version of the Resistor Indicator Module (RIM©) :) for my 12 pin plug set up.

Each resistor runs from the +L & +R in the 7 pin round to the -ve in the 7 side of the 12pin flat.

Hook her up, shut the LR 4 door, indicators flash, trailer detected.

(Yes, with this set up the car will detect a trailer with only the harness plugged in, but I never drive like that, so it's not a problem. Plus, this way I can connect any trailer with LED lights and the harness will do it's job)

The Resisters are simplybolted to the square metal tubing, keeping them away from plastic/rubber/wiring etc.

$40 for the resistors and a fun half day making it all up and testing and making it look neat.

Thanks again!
139447

[Aussie Jeepster]

I just want to say a big thanks to Peteren (and the wider AULRO Community) for posting this photo solution to the D4 LED Caravan lighting issue.

(I was also amazed at how little information I could get from official LR outlets when making enquiries about a fix for what is sure to be a fairly widespread issue)

Anyhow, based on the photo above and information in this forum, I made my own version of the Resistor Indicator Module (RIM©) :) for my 12 pin plug set up.

Each resistor runs from the +L & +R in the 7 pin round to the -ve in the 7 side of the 12pin flat.

Hook her up, shut the LR 4 door, indicators flash, trailer detected.

(Yes, with this set up the car will detect a trailer with only the harness plugged in, but I never drive like that, so it's not a problem. Plus, this way I can connect any trailer with LED lights and the harness will do it's job)

The Resisters are simplybolted to the square metal tubing, keeping them away from plastic/rubber/wiring etc.

$40 for the resistors and a fun half day making it all up and testing and making it look neat.

Thanks again!
139447

I do like that simple mod for the resistors.
Can I ask a question about your wiring to the 12 pin plug please?
Did you use heavier wire for the higher current pins from the white/grey 7 pin plug? Or did you go with normal trailer wire??
Thanks
Alan

[CBurgo]

Hi Alan,

Yes, heavier gauge wire on the white plug for the fridge hot wire, Trailer brake away battery (Only) and earth. (I dont use this plug for Auxiliary batteries, using a separate anderson with 6 B&S instead)

I think 8 B&S from memory. (Cant remember exactly, but pretty sure it was that.

Biggest wire I could fit in the terminals of the 12 Supplementary plug.

Hope that helps

[JAYRO]

This seemed like a solved issue so after reading the forum I bought two 21w Narva Resistors and put them in (one on each indicator wire / yellow and green ) and yet my MY15 Disco doesn't recognise trailer attached still.... urgh. Indicators and everything working as expected but no green trailer light on dash... Any ideas? Do I need to wire in 4? Do I need to wire them differently to make them work... Other seem to have fixed the issue with less hassle?

[DiscoMick]

Do the trailer lights actually work?
My Defender's light on the dash is reading the LEDs in the bullbar, not the trailer, but the trailer lights still work. I'm not familiar with D4 wiring though.

[Ferret]

... Any ideas? Do I need to wire in 4? Do I need to wire them differently to make them work... Other seem to have fixed the issue with less hassle?

You need to wire them in 'parallel' with your trailer indicator lights. You most likely have them wired in 'series'.

[veebs]

Do they get hot with the indicators on?

If not, something is wrong - need to be wired in parallel, not series as mentioned.

[JAYRO]

Do they get hot with the indicators on?

If not, something is wrong - need to be wired in parallel, not series as mentioned.

I re-wired in parallel and now the green trailer light in the dash flashes on in time with the blinkers... Uh?

- 21w load resistors on each
- there is an electric braking system installed for the caravan .. ( not sure if that is helping cause issue with detection )
- there is an ECB bullbar fitted with parking and indicator led lights.

[DiscoJeffster]

It’s meant to only show the trailer symbol when the indicators are on. That’s normal and indicates it’s working. The light is never solidly lit.

[JAYRO]

It’s meant to only show the trailer symbol when the indicators are on. That’s normal and indicates it’s working. The light is never solidly lit.

ok thanks. It's wired in and getting hot.

It raises the question for me though... am i getting all the features the car is meant to deliver when towing - such as as anti sway, different gear ratios etc...? to be honest I'm new to the Discovery and caravans, so not sure exactly how it's meant to behave when in combination.

[DiscoJeffster]

ok thanks. It's wired in and getting hot.

It raises the question for me though... am i getting all the features the car is meant to deliver when towing - such as as anti sway, different gear ratios etc...? to be honest I'm new to the Discovery and caravans, so not sure exactly how it's meant to behave when in combination.

Anti sway is there always, with or without the trailer wiring connected. It’s a function of the stability control function. Different gearbox profiles are supposedly enabled when you have the trailer wired in as you do so yes, you will benefit from that as well.

[Eric SDV6SE]

In my experience, when the car correctly detects that it has a trailer connected (via the turn signals- the car sends a milli volt signal down both L and R indicator every few seconds confirming it has a trailer connected) throttle response is modified, anti-sway (stability control) is amplified and vehicle braking is modified (I believe more bias to the rear brakes) and the EAS is also adjusted, so that the car does not auto level when stopped.

Im not sure if shifting patterns in the transmission are modified, I’ve not noticed. I have found that putting the transmission in S mode gives better performance, this is because the line pressure in the gearbox is higher in S mode, so it will hold gears longer, especially when towing. However I’ve had no dramas towing in “D” on long hauls.

I note that you also have electric trialer brakes on your camper, you need to ensure this is correctly adjusted so that the trailer does not “push” or “drag” the car when braking. If set up correctly, both car and trailer brake together. Combined with the cars ABS and braking adaptations, a very safe towing set up. I have the Tekonsha P3 electric brake controlled in my D4 and this allows me to adjust the voltage applied to the brakes, thereby adjusting how much braking is done. I found this handy as the camper weight changes each time depending how much water, camping gear, food, etc is stowed.

Hope this helps,

cheers,

Eric

[DiscoMick]

Yeah, we also have a P3 and it's neat to push the brake and get a reading on the P3's screen of how much pressure the brakes are applying.