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[Andy B]

My 'new' caravan has led front & side marker lights. My problem with them is that they flash continuously whether the car's lights are on or off. So it's been suggested to me that it's the car's CANbus lamp check & I need to fit  load resistor across them.
My question is ....... what value of resistor am I fitting? Looking on eBay there are loads of 6ohm clicky bu they seem to be for a bigger indicator, whereas I have just 3 little leds - 1 front & 2 side marker each side.

Any suggestion of a resistor size would be most welcome

TIA

[Bigron]

Andy, whilst you were on eBay, did you not look at CANbus LEDs that are a direct replacement for your existing lamps? Not knowing exactly what type of ;amp you are currently using, I can't give you a ;ink, sorry.

Ron.

[Andy B]

Andy, whilst you were on eBay, did you not look at CANbus LEDs that are a direct replacement for your existing lamps? Not knowing exactly what type of ;amp you are currently using, I can't give you a ;ink, sorry.

Ron.

The led is integral to the fitting

[biggriffin]

There's posh, pikey house's, now have led lights, to offset there carbon footprints, for when they use red diesel.

[Andy B]

There's posh, pikey house's, now have led lights, to offset there carbon footprints, for when they use red diesel.

One manufacturer went the whole hog with led tail lights but it seems they caused that many problems with different nake towcars they've gone back to normal filament bulbs

[Kevin Wood]

Are these markers on the same circuit as the tail lights and number plate lights and are the latter also LEDs or incandescent?

I'm just thinking that, if you already have a few incandescent lamps on the circuit, it will have plenty of resistive load, and adding more may not help.

My guess is that the driver circuit pulses the lamps for a sufficiently short duration that incandescent bulbs don't start to light, but the LEDs give instant light output, so it's noticeable. More load on the circuit probably won't change that.

Where you need to add load resistors to LED lights is in indicator circuits, where the flasher unit is sensitive to the current drawn and will flash fast if too little current is drawn from the circuit.

But.. to answer your question, a 6 ohm resistor will dissipate about 24 watts when driven from a 12V supply, so it's a similar load to a single 21W brake / indicator lamp.

I suppose, if you had 5 watt bulbs in your marker lamps, they'd add up to something around that figure so a single resistor that size would be worth a try. I just have some reservations as to whether it will help.

[Andy B]

I've not looked properly yet. All the rear/tail light are conventional filament bulbs, but the front and side marker lights are led built into the reflector. I'm hoping the are wired up separately from the rear lights that I can try a resistor across them. The pulse is just an opinion from someone else that suggests it's coming from the car's light check

[henryd]

I've not looked properly yet. All the rear/tail light are conventional filament bulbs, but the front and side marker lights are led built into the reflector. I'm hoping the are wired up separately from the rear lights that I can try a resistor across them. The pulse is just an opinion from someone else that suggests it's coming from the car's light check

Is the car towing wiring via a 7 way bypass relay or are you on the new style combined set up

[Andy B]

I've not looked properly yet. All the rear/tail light are conventional filament bulbs, but the front and side marker lights are led built into the reflector. I'm hoping the are wired up separately from the rear lights that I can try a resistor across them. The pulse is just an opinion from someone else that suggests it's coming from the car's light check

Is the car towing wiring via a 7 way bypass relay or are you on the new style combined set up

I didn't wire it up  It looks like a dedicated loom, but was originally only a 12N, a local towbar place swapped it for a 13 pin

[Kevin Wood]

Both plugs have separate terminals for left and right tail lights, so I'd first check what's wired to each. If they are correctly wired to their respective tail lights and they are incandescent bulbs, then I'm not sure it's going to help, but, if you find the tail lights are on one feed and the LEDs on the other, then loading that latter feed a little more may help.

[Andy B]

....
 if you find the tail lights are on one feed and the LEDs on the other, then loading that latter feed a little more may help.

That's what I'm hoping to find ...... I've had to go to work  so not been able to look

[Entwood]

Give Sargents a ring and have a chat .. they are without doubt the best when it comes top sorting car/caravan incompatibility .. they even make plug in boxes to sort out the problems !!

https://sargentltd.co.uk/

don't know if your new van is a swift or not .. but they specalise in these ..

https://sargentltd.co.uk/shop/product/led-road-light-electronic-control-unit/240

[Andy B]

Give Sargents a ring and have a chat .. they are without doubt the best when it comes top sorting car/caravan incompatibility .. they even make plug in boxes to sort out the problems !! ...

Actually ... they already have the alarm from my caravan, a fault it seems with the tilt sensor part  so I emailed them my question last night. 

[zirk]

My 'new' caravan has led front & side marker lights. My problem with them is that they flash continuously whether the car's lights are on or off. So it's been suggested to me that it's the car's CANbus lamp check & I need to fit  load resistor across them.
My question is ....... what value of resistor am I fitting? Looking on eBay there are loads of 6ohm clicky bu they seem to be for a bigger indicator, whereas I have just 3 little leds - 1 front & 2 side marker each side.

Any suggestion of a resistor size would be most welcome

TIA

Doesn't make sense that they are flashing on there own without any car lights / indicators on, which may indicate an issue or miss mash in the tow bar connector(s)?

Being leds, would they have there own flasher circuit built in?, and are wrongly being fed by voltage somehow, not convinced fitting additional resistive loads is going to help, tending more towards check the wiring first. 

[Andy B]

.......

Doesn't make sense that they are flashing on there own without any car lights / indicators on, [/quote]
hence my question  These marker lights are just that, nothing to do with indicators

which may indicate an issue or miss mash in the tow bar connector(s)?

All was well with the caravan lights of my previous caravan with the same tow car  and I have checked for loose connections etc & water ingress of the both plug & socket. And as said, the filament bulbs at the back are working as the should.

Being leds, would they have there own flasher circuit built in?, and are wrongly being fed by voltage somehow, not convinced fitting additional resistive loads is going to help, tending more towards check the wiring first. 

I also have a Smart Fortwo that the previous owner has fitted a led festoon bulb to the interior light. Even when switched to come with the doors open, it's never quite off when the doors are shut.  They're peculiar things these leds


The Merc's light check is different from the Omega's. On the Omega, you had to turn your lights on for it to check them, same with the brake lights, the Merc though can tell you as you turn the ignition on. I understand it's done via CANbus, but as that is way beyond the scope of a simple fitter, I've no idea how it does it.