Warning! Don't get a trailer with LED lights!

[backdoc]

My god. What a day. Bought a new kart trailer. Drove from Melbourne to Moama, NSW, to pick it up. After getting up at 4am to watch soccer wasn't looking forward to 6 hours behind the wheel.

A 10 year old landcruiser tows it to the meeting point, all lights working. Hitch the trailer to the Skoda Octavia RS and LEDs start blinking at about half strength and indicators and brake lights not working.

Some quick investigation revealed an incompatability between the CANBUS of the vehicle and the LEDs. Apparently due to such low power requirements of these lights, the car thinks there is a problem with them. Bought 1 resistor from Autobarn in Echuca and this got the left indicator working and the right ocasionally and the brake lights worked. Bought another resistor to attach in the line between car supply and right indicator. These seems to have mostly sorted it but some odd light flickering still remains. Looks like another 2 resistors will be required for each of the tail/stop lights.

And the point of this rant? Surely LED technology is developing in European countries faster than here. Why isn't this sorted? No Skoda assist or VW tech new anything about why we were having this trouble. It meant I was stuck for over 3 hours trying to fix the situation with no tools and some borrowed scissors and cigarette lighter. Nightmare :/

[The_Hawk]

It's actually a really common problem with the replacement LED globes you can get for taillights, essentially the old vehicles just throw power at the lights and hope everything is OK where newer and fancier cars expect a certain resistance and chuck a wobbly when they don't get it.
I believe some of the LED kits actually have a resistor built in to combat this problem, and yes a resistor one each light should solve your problem (either that or a new set of non LED lights ).

[CanberravRS]

Mate of mine fried his entire Trailer wiring due to LED lights and the Trailer shop not fitting the correct plug which has a resistance built in.

[STV4SYT]

If you get the proper wiring kit it works.

[backdoc]

If you get the proper wiring kit it works.

Please explain. I'm a novice with this stuff.

[Maverick]

My god. What a day. Bought a new kart trailer. Drove from Melbourne to Moama, NSW, to pick it up. After getting up at 4am to watch soccer wasn't looking forward to 6 hours behind the wheel.

A 10 year old landcruiser tows it to the meeting point, all lights working. Hitch the trailer to the Skoda Octavia RS and LEDs start blinking at about half strength and indicators and brake lights not working.

Some quick investigation revealed an incompatability between the CANBUS of the vehicle and the LEDs. Apparently due to such low power requirements of these lights, the car thinks there is a problem with them. Bought 1 resistor from Autobarn in Echuca and this got the left indicator working and the right ocasionally and the brake lights worked. Bought another resistor to attach in the line between car supply and right indicator. These seems to have mostly sorted it but some odd light flickering still remains. Looks like another 2 resistors will be required for each of the tail/stop lights.

And the point of this rant? Surely LED technology is developing in European countries faster than here. Why isn't this sorted? No Skoda assist or VW tech new anything about why we were having this trouble. It meant I was stuck for over 3 hours trying to fix the situation with no tools and some borrowed scissors and cigarette lighter. Nightmare :/

A correctly wired trailer wouldn't have had this fault occur, someone has slapped some LED's on a trailer without any regard to the cars out there that are smart enough to check bulbs (generally only euro cars as most other cars are too stupid to tell you when a brake, tail, number plate, head or indicator light has failed). The reason for the flashing is the car is testing for the presence of bulbs and it's smart enough to test the trailer lights along with knowing a trailer is fitted and adjust the stability control system to take this into account. In a conventional system if one of the trailer lights was damaged and shorted out this would take out that same circuit on the car and if a bulb had enough internal resistance it could start a fire whereas with bulb diagnostics it would be shut down for drawing too much power and the driver alerted.

VW and Skoda techs would know all about this problem, Skoda assist on the other hand is a service to get your car running again after a minor problem (flat battery etc) or tow it to a dealer so I'm not surprised they couldn't offer any advice seeing as they're not VW or Skoda trained.

Don't blame the technology or the car for what is really nothing to do with them, it has nothing to do with CAN bus at all and has to do with bulb diagnostics which does not rely on CAN bus to operate. It's just an unfortunate set of circumstances that ended up with you spending some time with the trailer!

[K1W1]

generally only euro cars as most other cars are too stupid to tell you when a brake, tail, number plate, head or indicator light has failed

Mazda, Toyota and Subaru all has systems that did that in the early 1980's somewhere along the line they were removed I suspect for cost reasons.

[Calais]

I had this issue with the CANBUS system on my Fiat Punto.

I had to rewire my entire trailer to match up with the Fiat requirement for less than a 5 amp draw. I managed to sort the total draw down to 3.8 amps when the trailer was fully lit up.

Its just a sensitive system, but it can be all sorted with a little patience and a multimeter.

Best of luck mate.

[dazag]

I had a similar problem on my RS, but as it turns out it's the Elec Control Unit for the trailer wiring that was stuffed (from new mind you - this was the first ever trailer hook up), I then tried 3 other normal globed trailers with same results. Back to dealership for warranty repair.