LED Hazard. Problem

[choogh]

My car has failed the IVA inspection due to rear hazard and side repeater lights showing dim amber between flashes. i.e ( On-dim-On)
However the two front indicators are OK (On-Off -On)
All six lights (front- repeaters- rear) work perfectly in indicator mode.
The flasher unit is for LED lights.

The car..


I do need help. As I have no idea what to do to solve the problem.
Cheers
Charlie

[GreenV8S]

If the flasher unit isn't compatible with the type of bulbs you're using then I suggest you change it for one that is.

[choogh]

The flasher is suitable for LED bulbs.



Thanks.

[gruffgriff]

I have no idea what I'm talking about but...is there room in the side repeater assembly to take the same bulbs as the front and rear? Or at least swap bulbs across to test and prove a point. If they are indeed different of course.

[GreenV8S]

choogh said:

The flasher is suitable for LED bulbs.

Are all the indicator and repeater bulbs LEDs?

[choogh]

All bulbs are LED, including the headlights.
Cheers
C

[Smint]

When we picked up new German built tanker trailers around 6 or 7 years ago, they all came with LED lights, recent modifications previously the lights had all been standard with normal bulbs, sometimes the lights on these LED equipped trailers failed to operate properly, when this happened the electrician on site would wire a resistor of some sort inside each main light unit, then all was well.
Might be worth mentioning to your auto-electrician?

[E-bmw]

What does the wattage of all bulbs together add up to?

Check all "bulbs" are the same, if the rears/sides are different, change them, all should be the same.

[tegwin]

You may find there is a little bit of current leakage somewhere. Either induction from other components or a faulty flasher or light unit. (Maybe even in your dash repeaters)

I’d look at the flasher unit first.

You could add a snubber to the wiring at the back of the car to prevent the transient voltages but that’s a bandage not a fix.

Lovely little car by the way ☺️

[choogh]

Thanks for the response. I’ve changed the flasher out on a like for like basis, but no change in operation.
What’s a “Snubber” in this context?
Thanks.

[Rockets7]

Does it have a tell tale indicator lamp on the dash and if so is it and old skool bulb type? If it is change it out.

[Arlen]

choogh said:

Thanks for the response. I’ve changed the flasher out on a like for like basis, but no change in operation.
What’s a “Snubber” in this context?
Thanks.

I am not sure what a snubber is but I assume this would be a diode of some sort as they only allow current to flow in one direction so the lamp could not backfeed.

[GreenV8S]

My guess is you've got an electronic flasher unit which is not fully isolating the output in the 'off' phase. You could confirm that by checking the output voltage at the flasher. Incandescent bulbs need a minimum current to get hot enough to glow, but LEDs will glow with any current at all.

As somebody else said, one way to address that is to put a pull-down resister in parallel with the LED to keep the LED voltage below its bias voltage (usually about half a volt) during the 'off' phase.

[tegwin]

Arlen said:

I am not sure what a snubber is but I assume this would be a diode of some sort as they only allow current to flow in one direction so the lamp could not backfeed.

What you are looking to do is to dump the rogue charge from the circuit.

Perhaps try this RC snubber - fit it a the back of the car between signal and ground for the indicators. (one for left and one for right if you wish)
https://www.ebay.co.uk/itm/285232323624?_skw=snubb...

[choogh]

Cheers Guys. Problem solved, installed resistor (aka Snubber) as suggested,
Thanks to All.
C