One of the LED DRL is not working

[Governa]

So today I noticed one of my DRLs is not working.



So what could be causing it? I’m quite far away from the nearest Smart Centre so I would like to try and fix it myself if it turns out to be an easy job. The car has only 15.000 kms/9.300 miles to the clock so I’ll be pretty annoyed if they just burned out.

It’s a 3 year old 451 with factory fitted DRLs.

[tolsen]

Burnt out LED filament.

[Governa]

LEDs have filaments?

[tolsen]

LEDs have filaments?

I am unsure abaut the inner workings of LEDs but surely their must be a filament somewhere since otherwise no way they will light up.

[lalli_d1]

I am unsure abaut the inner workings of LEDs but surely their must be a filament somewhere since otherwise no way they will light up.

http://electronics.howstuffworks.com/led.htm

second paragraph, 2nd line.

'But unlike ordinary incandescent bulbs, they don't have a filament...'

the electronics have got water in and have burned the PCB, more than likely

[Evilution]

No filaments but they can still burn out. LEDs generally fail from over heating or water ingress.
Check the electrical connection to the LED unit. Depending on if they are wired in series or parallel, 1 LED failure could knock out the rest.

[tolsen]

LEDs have a resistor connected in series to control current. Forward voltage of white LEDs is typically 3.3 volts. LEDs for 12 Volts systems are nearly always connected in series since source voltage is 12 - 15 Volts. They can of course be connected in parallel but that will require a much higher wattage resistor compared to connecting in series. These high power LEDs will most likely have a voltage and possibly a current regulator to drive them, i.e. a LED driver.

[Governa]

OK so the problem is water ingress on the 3rd LED. If you look closer you can see on the picture the little water droplets inside the LED casing.



Smart is quoting me €260 for a new one (ref. 4518200061). I guess I'll try eBay first...

[Governa]

It's worse than that, the €260 is just for the loose Hella LEDs (part no. 4518200061) like the picture bellow. That means that besides the €260 I would still have to pay for them to remove the broken Hella LEDs from the casing and then get the new ones installed.



So I've just checked eBay and was lucky enough to source a pair of DRLs like mine, original Smart Brabus (part no. A4518260718 and A4518260818) full set with casing & Hella LEDs, for €263. I've popped the broken set out, unplugged, plugged the new set and popped it in. Problem solved. So for the same price I've got two full sets instead of one loose string of Hella LEDs.

[Governa]

By popular request please find bellow a pic from the back of the unit.