Indicator flash rate for LED taillight cluster.

Izabarack · Guru

Indicator flash rate for LED taillight cluster.

Whenarewethere · Guru

Discuss your predicament on a forum for your particular model of car. It's a CAN-bus issue. The CAN-bus on pretty much all cars these days has been an issue for the last decade. My car is a Land Rover & it is a major issue with most rubbish from China, fifth rate LED cost cutting so called design.

kgarnett · Senior Member

A couple of suggestions:

https://www.superbrightleds.com/blog/led-turn-signals-blinking-too-fast-hyperflashing/275/

https://visual.ly/community/Infographics/how/4-ways-get-rid-hyper-flash-led-turn-signal-lights

Ken

rgren2 · Guru

You can purchase a LED flasher relay to replace the original, not expensive, jaycar have them.

Are We Lost · Guru

As Whenarewethere first said, it's a common CANBUS issue with modern cars. The fast flashing is a warning that the vehicle thinks a globe in the circuit has blown. The LED lights consume far less power than incandescent.

It seems silly as we progress to nearly all lights being LEFD technology, but the solution is to create additional power draw to simulate incandescent globes. Most auto shops have load resistors specifically for this purpose ... see the link from kgarnett. Connect between the positive side of the lamp and earth so it wastes a bit of power.

Supercheap load resistors

Don't get the ones for speakers.

Izabarack · Guru

Very useful replies, thanks. Im going to go the resistor solution. Will be easy enough to add into the wiring and to mount the resistor so the resistor uses the chassis as a heat sink.

Mamil · Senior Member

I had a similar issue, not the flashing rate, but the car couldn't detect the trailer was there to activate it towing features, so I added a pair of these load resistors to the indicator circuits, $29 from Repco.

Load resistors 1.jpg

jegog · Senior Member

Are We Lost wrote:
As Whenarewethere first said, it's a common CANBUS issue with modern cars. The fast flashing is a warning that the vehicle thinks a globe in the circuit has blown. The LED lights consume far less power than incandescent.

It seems silly as we progress to nearly all lights being LEFD technology, but the solution is to create additional power draw to simulate incandescent globes. Most auto shops have load resistors specifically for this purpose ... see the link from kgarnett. Connect between the positive side of the lamp and earth so it wastes a bit of power.

Never fit a resistor in parallel with the lamp(LED or incandescent). Sensing blown globes is done by providing a sense current through the lamp. Not enough to illuminate it but enough to detect an open circuit.

Are We Lost · Guru

Well, the internet must be wrong. If you search for "wiring load resistor" you will find countless links saying to do exactly that. It works fine for me. Mamil posted an image of a load resistor from Repco. If you go to that page you get the wiring diagram.

jegog · Senior Member

Did you read the product label.

They are for preventing blown globe warnings.

When a relay replacement is merely a matter of pulling the relay out of the fuse panel and inserting the replacement, why would you bother with altering the wiring and drilling and mounting a load resistor?

Are We Lost · Guru

That is exactly what happens ....a blown globe warning when nothing has blown. On the packet it says ..

"For use when fitting LEDs to late model vehicles that display light failure warnings". To me that is quite clear that it is not to fix any failed part.

It's handled by software in the BCM (Body Control Module). I doubt there is an accessible relay in modern vehicles and even if there was, with the vehicle under warranty I would not be replacing it with a non standard part when this does the job.

The fact that these are available everywhere and a known solution to the known problem, I don't understand your objection. Anyway, I have said my piece and you are welcome to continue without me any more.

Izabarack · Guru

Are We Lost wrote:

"For use when fitting LEDs to late model vehicles that display light failure warnings". To me that is quite clear that it is not to fix any failed part.

My vehicle is not, and does not, display(ing) light failure warnings. So, if the suggested fix fixes my problem, then I will ignore the non-existent advice on the parts draw at the electronics shop from which I will source the resistors I will fit.

Incidently, the wiring loom that came with the towing pack on the vehicle includes a potted module, apparently containing appropriately sized resistors to cater for the LED lights on the caravan. The indicators on the caravan flash at the normal rate.

Are We Lost · Guru

Izabarack wrote:

My vehicle is not, and does not, display(ing) light failure warnings. So, if the suggested fix fixes my problem, then I will ignore the non-existent advice on the parts draw at the electronics shop from which I will source the resistors I will fit.
Incidently, the wiring loom that came with the towing pack on the vehicle includes a potted module, apparently containing appropriately sized resistors to cater for the LED lights on the caravan. The indicators on the caravan flash at the normal rate.

In my case the light failure warning is not on the dashboard, but the fast flashing of the indicators is the warning.

But when you say the indicators on the van flash at the normal rate. do you mean they flash at a different speed to the vehicle when connected? If so, that would be really strange and I can't imagine how that could happen .... unless it is within the potted module, whatever that is.

If going the electronics store route, just make sure to get big enough resistors that won't burn out.

Peter_n_Margaret · Guru

Izabarack wrote:
The indicator flash rate on my newly installed taillight cluster seems a little fast.
_______________________________________________________________________________________________________________
What is "a little fast"?
If my memory is good, the rules require between 60 and 120 flashes per minute.
If it is within those, do nothing.
Cheers,
Peter

Izabarack · Guru

Peter_n_Margaret wrote:
If my memory is good, the rules require between 60 and 120 flashes per minute.

Ok, that is good info. I have a handheld Optical Tacho so will measure the cadence. If the flash rate is within limits, then i will follow your suggestion.

Whenarewethere · Guru

Refer to 6.3.10.1 for flashing frequency

https://www.legislation.gov.au/Details/F2016C00338

dorian · Guru

I would argue that it's not a CAN bus issue. Instead the "problem" is in the Body Control Module (BCM). This is just one of several distributed "slave" processors which performs a specific task. These slave processors all communicate with the master controller via a pathway called the CAN bus.

https://www.st.com/en/applications/body-and-convenience/body-control-module-bcm.html

https://www.ti.com/solution/body-control-module-bcm

https://www.bosch-mobility-solutions.com/en/solutions/control-units/body-control-module/

jegog · Senior Member

The general rule is that LEDs require one quarter of the current of an incandescent lame for the same light output.
Assume a 12W globe. Incandescent requires 1A current and a LED 250mA.
Therefore the resistor will be required to conduct 750mA.
Two indicator lamps, therefore when both lamps are ok, 2A current.
One globe blows 1A current.
Now one LED not working 1.75A current. 12.5% less current with one faulty LED.
The original post was for a fix for flashing too fast with LEDs working and the fix was to use load resisters in parallel with the LEDs.
I think that the cure will make the flash rate difference too small to be reliably noticed.

Are We Lost · Guru

You misunderstand how the system works. The cure works.

The BCM knows a trailer is connected so it expects to see higher consumption than the car alone. If you have LEDs on the van, there is (often) not enough difference. So it detects that as a blown globe. It then activates the warning system which increases the flash rate to let the driver know of the problem. Maybe some vehciles have a dash warning .. mine doesn't. There is no variable flash rate depending on current. It is either in normal mode, or fast flashing mode. Nothing in between.

Also, your comment about the current draw of LED vs incandescent is too conservative. Most would be at least 6 times more efficient, with better figures for the better LEDs.

Greg 1 · Guru

Had this issue with my Ranger. Easy fix. Bought 2 x 120 ohm ceramic resistors from Jaycar for the princely sum of 0.69 cents. 2 in a packet. Wired them into the trailer plug between the earth wire and one to each indicator wire. Problem solvered.