Trailer light converter or LED upgrade

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nickb800

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#196014 16-May-2016 07:43

Gidday

I have a classic kiwi homebuilt trailer from the 80s, shared among the family. Lights are currently incandescent. Family members have been having trouble with the trailer lights causing errors in their modern cars, and indeed blew the brake light fuse in a 2016 model car last week. My 2002 car doesn't have any issues, and a quick inspection shows that there is no obvious damage to the cables or corrosion on the bulb fittings.

The obvious option is to get a trailer light converter installed in each modern car that regularly uses the trailer. But we'll probably need at least two cars fitted, and still presents problems when extended family uses it.

What I'm thinking is to upgrade the trailer's lights to LED, which should hopefully reduce the current load to a point where modern cars don't notice it, and don't throw up an error or blown fuse. One LED conversion kit has got to be cheaper and easier than 2-3 trailer light converters.

Does this sound like it will work?

illicit

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#1553393 16-May-2016 09:02

Get hold of a multimeter and test the resistance in the wires from the trailer plug to each light fitting first - may likely be a damaged cable (usually at a corner or junction)

If all OK then Yes - LED will dramatically decrease the load on the cars lighting circuit

Fred99

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#1553394 16-May-2016 09:06

No - it won't work on all modern can bus cars, even the reduced load from the LEDs may generate a fault.

In some cases the controller also interacts with braking/ESC systems.

There may be aftermarket light controllers available at considerably lower cost than OEM, but you need to check these out on a car by car basis, some generic controller may not be appropriate (ie re ESC as above).

Some cars may already have the controller circuitry, just needing to be wired up to a plug.

If fitting LEDs on a trailer which may be lent to/used by different people, get 10-30v lights. Most have 12v rated driver only, and will shine ever so brightly - but for a very short time - when somebody plugs them in to a 24V system, common on some diesel SUVs.

timmmay

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#1553395 16-May-2016 09:14

I wonder if some kind of a relay system could work, but that would require a power source on the trailer. A small battery should be easy to fit and keep charged, though I wonder if there are laws/restrictions around that.

Fred99

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#1553419 16-May-2016 09:27

timmmay:

I wonder if some kind of a relay system could work, but that would require a power source on the trailer. A small battery should be easy to fit and keep charged, though I wonder if there are laws/restrictions around that.

Some are relay based systems - and I believe that in some cases there are still problems with the small current draw from the relays with aftermarket units for some cars. I guess you could get all techo about it and design something which uses solid state relays with very small current draw, but that may still not get around the issue if the car has an ESC system which senses and adapts when trailer lights are connected.

It needs to be done correctly. The other issue is that with assorted cars with towbars, even if you could get a system to work with that trailer, then you're probably going to want them able to be used with other trailers, so may as well bite the bullet and do it properly from the start.

richms

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#1553575 16-May-2016 14:05

Unfortunately this is what happens when you cheap out on the non OEM towing package.

Get the manufacturer approved light controller and it will all be fine.

Richard rich.ms

MikeAqua

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#1553623 16-May-2016 16:02

Go LED lights on the trailer.

90 minute job to fit and you will never have trailer light issues again (except maybe the plug).

Mike

richms

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#1553625 16-May-2016 16:04

I got aliexpres LED festoon lights for my trailer. 12v only but I have cooked the flasher twice in the car parking with the hazard lights on so reducing the load on it has to be a good thing.

Richard rich.ms

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nickb800

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#1553628 16-May-2016 16:14

Okay, so mixed responses. Part of me is keen to go with LEDs anyway, as they are low maintenance and a sealed unit so less as likely to have corrosion/high resistance issues that can blow fuses even in my older car.

I'm tempted to put a connection box on the trailer with relays or SSRs to attempt a system that works with multiple cars.

I haven't found any more clever systems to work around can bus on eBay - they all seem to be resistor based which is just going to cause over current problems with trailer lights

MikeAqua

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#1553629 16-May-2016 16:20

Festoons still rely on being fitted into conventional contacts, so vulnerable to corrosion, loose contacts etc. I found (on my boat) they were more prone to corrosion than filament bulbs.

Ballpark for a pair of LED trailer light clusters is $50 - $150.

richms:

I got aliexpres LED festoon lights for my trailer. 12v only but I have cooked the flasher twice in the car parking with the hazard lights on so reducing the load on it has to be a good thing.

Mike

richms

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#1553631 16-May-2016 16:26

MikeAqua:

Festoons still rely on being fitted into conventional contacts, so vulnerable to corrosion, loose contacts etc. I found (on my boat) they were more prone to corrosion than filament bulbs.

Ballpark for a pair of LED trailer light clusters is $50 - $150.

Nothing a little solder doesn't solve. I left the incandesnt tail lights in since I couldnt find any dim enough LED's so that there was a difference between the tail and stop lights, so its still an ugly orange license plate light, but really I dont see any benifit for me in making that even easier to see. Its the brakes that matter so people dont drive into it. Tempted to stick a high level one up on the cage too.

For the OP, if the towing setup on their car cant supply 40-50 watts of power to each of the brake and indicator lights then its not really fit for purpose and they should get it looked at. Just simply paralleling up to the lamps in the back of the car hasnt worked for close to 20 years now on european cars and at least 10 on most others. Places that are still doing that are selling something that isn't fit for use. That's why many places are offering towbars with no wiring now since many people only want them for a bike rack or open home sign or similar, which has no need for the lighting.

Richard rich.ms

nickb800

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#1553718 16-May-2016 21:15

Yeah I was pretty surprised a 2016 hyandai with a >$1000 RRP towbar kit installed by the dealer didn't include a converter if it was super sensitive. What wasn't clear was if they had been given an option for a higher spec kit.

I might do a bit of experimenting, and try see which cars are happy with LEDs, which ones like resistors inline, and which ones just don't play nicely. I can make up a short trailer plug conversion lead with resistors in it for the ones that like it, and recommend the manufacturers kit for the two hard basket.

richms

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#1553732 16-May-2016 21:37

If you cant plug a trailer into it then I would start talking consumer guarentees act with the dealer about the suitability of their towing package.

Richard rich.ms

Fred99

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#1553766 16-May-2016 22:56

richms:

If you cant plug a trailer into it then I would start talking consumer guarentees act with the dealer about the suitability of their towing package.

I expect that they'll have that well covered. If buying a new car, it's something to negotiate as a no-cost extra. Towing packages at $2,500 (including controller) seem to be becoming the norm here in NZ.

There are "ZCI" (zero contact interface) kits made that don't splice into the car wiring, a sensor clamps over the wire. Not sure if they're available (yet) in NZ.

Some tow ratings are based on the ESC system adapting to when trailer lights are plugged in, Euro cars in particular. I doubt those aftermarket light kits will do the trick.

For some small cars, VW Tiguan etc, the tongue weight rating is very low (IIRC something like 80kg) yet nominal tow rating of 2,000kg or so (more than many large sedans) when they're sold in NZ. At that towed weight, then you'd normally have tongue weight of about 10% or a little more, less than 5% would be dangerous at speed. However with the correct lighting kit, the ESC "knows" a trailer is attached and adapts, and reacts to counter trailer sway if it occurs. Presumably if you're not using an OEM or aftermarket kit which communicates with the CAN bus system, it's potentially dangerous. It's also potentially dangerous if you're towing a 2t load like a tandem boat trailer set up "normally" with 200-250 kg tongue weight on a small car like that - and it will probably void warranty. The trailer wheel position or load placement should be changed, but then you've got the problem that if the trailer with light tongue weight is towed with a car without this kind of ESC system, then it will also be dangerous.

In the US, tow ratings for VW and Audi equivalents are only 50% of the tow ratings of the same cars sold in NZ. For example VW Tiguan 2.0 TSI 4-motion is rated for 2,200 pounds braked towing capacity in the USA, but it's rated for 2,200 kilograms here in NZ - more than double the US rating. IMO that anomaly really needs an answer, and some extra care / knowledge is needed when towing with recent vehicles.

You can exceed 2,200lb (just under 1,000kg) with a couple of scoops of builder's mix etc on a single axle trailer.

lxsw20

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#1553823 17-May-2016 04:23

richms: Unfortunately this is what happens when you cheap out on the non OEM towing package.

Get the manufacturer approved light controller and it will all be fine.

+1 I would not mess with a new car and not using the proper kit. I've seen a Passat destroy one of its many computers this way before. Then the push button handbrake would no longer apply.