LED bulbs.

[Westgatez]

Hi guys, small issue I may need some advice, nay, WILL need some advice on.

I have recently purchased these LED rear lights... 21W/5W

http://www.ebay.co.uk/itm/3515813749...%3AMEBIDX%3AIT

I did a little research, what I gathered was that these would replace my two filament halogens directly, with ease..

....however when the lights are on they are already at the brightness it would be when you are braking....

so, to conclude, when I brake, the rear lights don't light up, but instead stay at the maximum brightness they would when braking, all the time...

Thanks.

Hope this make sense.

[Piers1989]

I don't know for sure, but I'm pretty sure the dual filament ones have 2 completely separate connections. Each one takes 12v but one is low W and dim and the other is high W and bright.
If this is true you can't replace that with just 1 bulb (at least not without a microprocessor to determine which input is on and dim and brighten the bulb).

Sorry but if you've bought these to replace a dual filament I don't think they are ever going to work as you intend as they only take 1 input.

[Westgatez]

Interesting, I was going to reply with this then in that case, I previously had these in there..

http://www.ebay.co.uk/itm/2X-Red-580...4AAOSwAuZX6hIc

They worked like the halogen dual filament should, acting as a taillight and lighting up when I braked.

I went for a change because I wanted something that was a little brighter, which of course they definitely turned out to be, but not in the correct circumstances haha.

As you can see from the picture the blade fitment and wire arrangement is the same. So for this I am confused.

[Westgatez]

If you look in the description of the first link I posted...

http://www.ebay.co.uk/itm/3515813749...%3AMEBIDX%3AIT

It says, 7443 580 (Dual filament)

This I suppose relates directly to the halogen equivalent, so you know which LED bulb to choose.

[Piers1989]

I'll give you that it does say that, but I'm not really sure from a physics perspective how the bulb is meant to know what to do with only 2 connections. UNLESS the connections actually have front and rear "sides" slanted in different directions such that they contact both the brake and tail lights.

Then with a integrated controller or even a resistor or diode etc it could make one of them dim and the other bright.

Have you tried putting them in the other way around? If that doesn't work I imagine they will just not light up at all.

Maybe compare the angle of the connectors to your old bulb and try to bend / mimic it as closely as possible.

Otherwise pull one out and try attaching 1 side directly to your car battery with some wire (or a smaller 12v source if you have one for safety), then try the other and see if you do get 2 brightness levels.

[Westgatez]

I will try tomorrow, when its not raining : )

[Davezj]

do you have them the correct way round?
one way will put the brake light on as a brake light and the other will put the brake light on as the rear light. well that is what i would expect as i have fitted rear led bulbs in the past.
i removed them as the ones i had were just too bright and when just the rear lights were on it looked like i had the fog lights on. i had the 7w cob type.

[adaxo]

I will try tomorrow, when its not raining : )

Did it work at the end? as i need rear stop bulb so may upgrade them to LED too, if they work properly.

[Davezj]

I have just ordered some non cob led bulbs for the rear. So I hope they will be ok.
The cob ones are just too bright, it looks like you permanently have the fog lights on. And we all know how anoying it is to follow someone at night that leaves there fog light on.


Sent from my space-aged gizmo