Hi folks.
Rightly or wrongly I have fitted a set of LED daytime running lights made by a reputable aftermarket lighting supplier purchased for £60 from a well known automotive shop!
They actually look good and on the driveway with the engine running performed as they should.
When travelling above 30mph they start to flicker independently of each other. I cannot replicate this fault when revving the car at stand still, in brief the fault occurs on the move.
I have been back and forwards to the supplier and manufacturer who cannot offer a solution.
I have discovered that my year of RRS 2007 has a ‘smart alternator’ that sends pulses through the cars system checking circuits etc. I have heard that these aftermarket LED’s don’t like these pulses and will not function correctly.
I have tried wiring directly to the battery poles, wiring to a spare fuse and introduced a relay but to no avail.
I have seen YouTube clips of other makes of car using a capacitor or resistor that interrupts and absorbs the pulses when wired into the power supply to the DRL’s.
My question is has anyone experienced the same and can it be rectified etc.

Many thanks in advance.

When I fitted drl rings to mine I wired the live into a spare ignition live in the fuse box and earthed them to a nut on the bodywork in the engine bay, lights came on when ignition was turned on and went off when it was turned off, no flickering at all

well you have 2 choices.

1) try and resistor and capacitor
2) some how remove the cleaver circuitry in the lights and connect to ignition (but I guess half the circuit is required??)

jason-nike wrote:

When I fitted drl rings to mine I wired the live into a spare ignition live in the fuse box and earthed them to a nut on the bodywork in the engine bay, lights came on when ignition was turned on and went off when it was turned off, no flickering at all

Andy K wrote:

well you have 2 choices.

1) try and resistor and capacitor
2) some how remove the cleaver circuitry in the lights and connect to ignition (but I guess half the circuit is required??)

Got any links to the video's ?

I think you would need to know how much current the LEDs draw

If they are manufactured by ring, have you tried disconnecting the side yellow light wire?
Might be worth a go on the off chance that is the problem

or do still flicker with the cars side lights on ?

Hi Andy. Yes disconnected the yellow wire that connects to the lights.



This is one of quite a few that have appeared on YouTube since I last looked.

Humm... That could be a different issue

Pics of my drl’s

You hit the nail on the head in your first post, you need to add a capacitor between the input and your DRL controller. This will smooth the power and prevent the spikes/pulses caused by the alternator. If you fit a cap you will also need to fit a diode to prevent the cap sending power the wrong way when you switch off the ignition.

Thanks for the info. The diode sounds sensible. I think I will buy a capacitor and diode. A couple of queries remain though ie what specification/values do I need and is it a per lamp unit or can I use one on the feed to the lights in their loom before they split to each DRL light unit.

It will all depend on your setup. The diode and cap will need to be before the DRL controller/s. I would think that you only have a single controller that feeds both DRLs and has a live, negative and sensor input. So solder the diode to the cap (ensuring that it's facing the right way of course) then solder the other leg of the cap to the positive wire on the DRL controller, diode side goes to the ignition live.

For the diode you will be able to user a 1N5404, for the cap, something rated around 47uf and 25v will do the trick

As an FYI, the sensor wire will need to be reconnected as they need to dip when your headlights come one or you could be stopped by the rozzers!

EDIT:

Sorry, my explanation is clear as mud

The lamps are fed by the controller, so you need the cap and diode between the positive feed from the car and the DRL controller. You will only need a single diode and cap

That’s awesome. Many thanks for this. I will get some ordered and get out and fit them. I will wait for the beast from the east to do it’s worst then post the results.