LED trailer lights X5

[shuey 61]

Does anybody have the answer to the problems involved with fitting LED lights to a trailer towed by an X5 - ie fast flashing indicators and brake light on when tail light should be on.

Cheers

Shuey

[jochen 4]

Does anybody have the answer to the problems involved with fitting LED lights to a trailer towed by an X5 - ie fast flashing indicators and brake light on when tail light should be on.

Cheers

Shuey

Brake light vs taillight = you got the wiring wrong. Ensure the trailer connected is wired according to the standard.

Fast flashing indicators = this is the car telling you a bulb is blown, due to insufficient load. Fit a load resistor to the trailer to simulate a std light bulb

[shuey 61]

Thanks for your input, but I have not got the wiring wrong. Works perfectly behind my E30.

[*Glenn* 854]

Thanks for your input, but I have not got the wiring wrong. Works perfectly behind my E30.

The E30 & the trailer could have been done wrong together or the X5 is wrong

[shuey 61]

Again, thanks for your input. Researching the international forums it appears that this is a common problem. All to do with resistance within the circuit apparently. Yes, putting a bulb into the circuit does solve the problem, had the whole thing working beautifully today by wiring the old light fitting into the circuits, but that kind of defeats the purpose of fitting LED's.

[elmarco 56]

What are the LED lamps you have used? If they are Hella DuraLEDs you could try using the blue wire (from memory it's blue - it will be engraved on the back of the lamp) - the function was developed specifically to get around this problem by simulating the load of a bulb. It doesn't always work, but has fooled some systems into thinking they are bulbs. You are right in that wiring in another bulb or resistor to fool the system does defeat the purpose a bit.

There are LED specific flashers available, but they only work with specific Hella LED lamps. As to if they work with the X5 I can't say - not sure what type of flasher it uses.

[shuey 61]

Thanks. Yes they are Hella, not sure what model though but there is a blue wire. Try using it for what?

[hotwire 352]

Thanks. Yes they are Hella, not sure what model though but there is a blue wire. Try using it for what?

Shuey, The blue wire is the indicator load wire, connect it together with the indicator wire - this simulates bulb current

[jochen 4]

but that kind of defeats the purpose of fitting LED's.

LEDs have 3 key benefits:

1. Ultra Long Life

2. Super fast on-time

3. Low current draw

Only item #3 is affected by fitting a load resistor.

You cannot change "flasher units" as there are none on a BMW.

The Lamp Control Module monitors the state of all lamps and controls them. When a trailer is connected, the Trailer Control Module checks the trailer lamps in the same way and reports to the Lamp Control Module via a databus if the trailer lamps are OK.

The only way the control units can check if a bulb is OK is to measure the load, and this is where LED lamps fool the system.

Experiment with a resistor wheel to find the highest value resistor (and thus lowest current drain and lowest heat dissipation) that you can use to fool the lamp checker circuitry in the car.

By fitting a resistor to the trailer, you make the trailer compatible with all cars, not just your X5.

[shuey 61]

Thanks for all your help guys.

[shuey 61]

Thanks for your help Jochen. All sorted and working now. Cheers.

[deeveus 81]

With the faulty channel error i.e your brake light coming on the trailer when the lights of the car are on, this is the problem I was having aswell, even with a new trailer. I understand you've resolved the issue by adding a resistance system but I thought I'd add my share of events when I went through the same thing...

When you plug in a trailer it puts the vehicle into a trailer mode*** & it makes the car think that your bulbs are out because it adjusts things to suit the extra draw. Quite simply you need a module fitted to the trailer which will make the current draw the same as a bulbed setup, you can still use your LED equipped trailer then.

I went through this the hard way when I bought a brand new alloy trailer with LED lights. I had the same issue with my Range Rover and Touareg. My mechanic actually made a system up so that with each channel, i.e brakes, lamps, indicators had a bulb which created the resistance enough so that it didnt upset the cars computer. I've had about three cars that had the problem but with the module fitted the problem dissapeared!

***Trailer mode changes the cars stability control, stays in gear longer, allows the alarm to go off if the trailer is removed when the vehicle is armed/locked and adjusts the current draw for the bulbs for lamps, indicators and brake lights. There are other things it changes on the car too but I can't remember them all!

Edited August 14, 2010 by Clinton

[Nobimmer 694]

[jochen 4]

Let's correct a few technical errors here.

When you plug in a trailer it puts the vehicle into a trailer mode*** & it makes the car think that your bulbs are out because it adjusts things to suit the extra draw.

No, it doesn't "adjust" anything for the extra draw. It's much simpler.

When you plug in a trailer, the Lamp Control Module (LCM) expects to have a current draw equal to a normal tungsten filament lamp.

When the current draw is too low, ie: lamp blown, or LEDs fitted, then the LCM says: lamp is faulty. And takes whatever actions are appropriate for a faulty lamp (indicators flash faster, or warning light on dashboard, or uses backup system to use other lamps as a failsafe).

Quite simply you need a module fitted to the trailer which will make the current draw the same as a bulbed setup, you can still use your LED equipped trailer then.

Correct, you need to fool the Lamp Control Module into thinking that a normal bulb is fitted.

[yng_750 247]

this thread is very old but i will post anyway

narva sell a load resistor for about $25 designed specifically for this problem

that being said almost every led trailer lioght you buy now has a resister built in, didnt take them long to figure out people want a plug in job rather than a faff around.

[elmarco 56]

this thread is very old but i will post anyway

narva sell a load resistor for about $25 designed specifically for this problem

that being said almost every led trailer lioght you buy now has a resister built in, didnt take them long to figure out people want a plug in job rather than a faff around.

It isn't quite as simple as that - a resistor gives a linear voltage/current relationship where a bulb doesn't. Some systems can be fooled by a simple resistor, others can't - depends what they are and what they look for. You are correct in that nobody wants to faff around with them though - plug & play is the only way. Hella spent many many thousands of hours and dollars solving this and have a number of patents around it. Some of the elcheapo chinese knockoffs will have a resistor, but it won't work with all of the systems out there.

While it is a pain for the average euro car owner, it gets infinitely more expensive (and painful) when the trailer has 12 wheels, weighs 30 tonnes and the brakes won't unlock because the tractor unit uses the lamp circuit to detect if a trailer is attached (and unlock the trailer brake circuit) and won't recognise LED's...

[yng_750 247]

It isn't quite as simple as that - a resistor gives a linear voltage/current relationship where a bulb doesn't. Some systems can be fooled by a simple resistor, others can't - depends what they are and what they look for. You are correct in that nobody wants to faff around with them though - plug & play is the only way. Hella spent many many thousands of hours and dollars solving this and have a number of patents around it. Some of the elcheapo chinese knockoffs will have a resistor, but it won't work with all of the systems out there.

While it is a pain for the average euro car owner, it gets infinitely more expensive (and painful) when the trailer has 12 wheels, weighs 30 tonnes and the brakes won't unlock because the tractor unit uses the lamp circuit to detect if a trailer is attached (and unlock the trailer brake circuit) and won't recognise LED's...

ill clarify the load resistor/ inbuilt resistor i was talking about is just there to stop the indicator flashing at a million HZ

i was under the impression it would stop teh check lights but maybe not

As you say going genuine narva or hella are your best bet

they are from europe so will understand those sorts of cars, they dont cost that much more than chinese and they have lifetime warrenties and "unbreakable" lenses

Cost about $120 for a pair at supercheap

As opposed to $70 for chinese + $80 per hour it takes for a sparky to fix the issues

Edited June 3, 2012 by jason H

[Micky_d01 0]

http://www.ledtowconnect.com/2012/06/bmw-x5.html?m=1

 

^ this is the solution to LED trailer lights.