I am having problems in conjunction with the Caravan electrics design and manufacturers, when my RR SC is connected to my new caravan which has full LED lighting there are major problems, most of the problems have been solved with a unit provided by the caravan electrics manufacturer but i would like to know with the help of my IID tool i could tell the car that the trailer/caravan to ignore the fact that there is no filament bulbs fitted to the trailer/caravan and get the last fault with the lights sorted out?

Problem now ?
After 5 flashes of the indicator any side the car decides to flash only the car indicators very fast, the rear brake lights on the caravan flash on and off constantly when the engine is running, if the engine is switched to Aux everything works fine.

Any help would be appreciated. [/b]

I used to have the same problem with my boat trailer (with LED's)

As far as I know, the only way to fix it is to install ballast resistors.

The problem is the car is trying to be too smart - it's looking for the 'load' created by a filament bulb & the LED is too efficient, so it thinks something is wrong / broken etc.

It depends how handy you are as to whether you can take on the job yourself - I put 50W resistors in the draw bar of the trailer - you need one for each circuit & they are wired in parallel to the LED - so basically one side to each of the bulb circuits & the other side to ground.

Something like these on eBay

Some 'van makers are acknowledging this as an issue and have a fix. Friend with a 16 plate D4 HSE has just had the 'fix' fitted to his 2016 Bailey Unicorn and all is well now.

There may be an interim measure but beware of warranty issues....as you know 'van makers are not the best when it comes to warranty. Is this where I put the car details and a bit about myself ?........

How bloody stupid for van makers to use LEDs for indicators.

Are they getting their own back,


What do you mean by engine switched to Aux ?

A lot of finger pointing on this one - even after car makers were using LED's in their cars, they still require filament bulbs for the towing electrics

Definitely a lack of coordination, but I would blame the car manufacturers for not being able to deal with LED's

I assume Aux is first key position - so the engine isn't running & the car isn't actively trying to figure out ir all the bulbs are working and the trailer is still connected.

At least it was a known standard.

A trailer would have a 21W indicator. Easy.

Very easy to deal with.


To the OP. Try fitting load resistors to the van brake lights.

So what problems did fitting a box to the caravan solve ?

Everything apart from the indicators stopping working after 5 blinks with the engine running, they fitted a balast resistor to stop the break lights from blinking so that fault went away

As discussed above the reason is that LED units do not provide a sufficient load to allow the car to know a trailer is connected. There are units available on the market which claim to eliminate this issue although I've yet to find one which works properly with a FFRR. They do seem to work OK with a Disco 4 though.

My solution was to apply Ohm's Law and use some wirewound resistors to increase the load that LEDs draw and allow the car to think a normal filament bulb is present. They should be wired in parallel with the LED and thus shunt some extra current to ground.

Values vary on the size of the bulb, hence Ohm's Law. V (Volts) = I (Amps) X R (Resistance) and P (watts) = Volts X Amps
Thus for a sidelight which should be 5 watts I got 12v = approx 0.4 amps. and so 30 Ohms resistor which can take 1 amp of current. (per bulb)
A brake light, which should be 21 watts, would need 7 Ohms and be capable of sinking at least 2 amps. (per bulb)
Indicators are also 21w, as are fog lights. I didn't bother shunting the reversing units.

Values should be taken to the nearest available as resistors come in specific values. As long as you're +/- 20% it will be fine. Worth remembering that wirewound resistors get hot, that's how they sink the current. I bolted mine to an ally plate and tapped into the main cable at the front of the caravan and mounted the plate in the front locker where it's in the airflow. Don't tape them into the loom as I have seen done.

What caravan is it you have that's causing you the issues?

it is a 2016 Bessicarr 645 manufactured by Swift Group

Swift and another manufacturer have these leds as a known fault on some cars.

There is an adapter they supply free with basically plugs into the car 13pin socket and then you plug the caravan into that.


EDIT.
It is made by Sergent who do the swift electrics and it sits near the caravan consumer unit. Little box filled with the required electrics to made the caravan LEDs run correctly.

mzplcg wrote:

There are units available on the market which claim to eliminate this issue although I've yet to find one which works properly with a FFRR.

If you fit resistors across the indicator leds and the leds fail you will not get any warning that the indicator has failed.

It is a legal requirement to get a warning that your indicator has failed.

Ian