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General forum area => K1200 / K1300 Forum => Topic started by: billski on July 13, 2018, 10:57:05 am

Title: Back light failiure
Post by: billski on July 13, 2018, 10:57:05 am
Hi, i have a 2010 K1300R. Just noticed today that the two of the brake light LED's have blown/stopped working. I have been told that the light is a sealed unit so i will have to fork out for a new one, question is has anyone had one of those clear black tint lights fitted, if so, are they any good and where can you buy them from.
Thanks in advance.
Title: Re: Back light failiure
Post by: Philip on July 13, 2018, 01:07:31 pm
Mine failed like that about 4 years ago.

Although it's a sealed unit, with judicious use of a sharp knife & other leavering implements, you can get the lens unit apart where the two halves are glued together in manufacture.

The power driver had failed on the PCB, but as they are micro sized chips I didn't think it was possible to renew the chips easily.

I bought a dozen 12 volt high brightness red LED's off eBay similar to these   -    https://www.ebay.co.uk/itm/12V-Pre-Wired-Ultrabright-Waterclear-5mm-LED-Various-Colours-LEDs/261319713773?var=560239458731&hash=item3cd7de63ed%3Ag%3ATRkAAOxyAc1STZBL&LH_PrefLoc=1&_sop=15&_sacat=181880&_nkw=5mm+red+12v+leds+10&_from=R40&rt=nc

Bought a plastic screw connector block ( strip of 12 which you cut 2 off ) from Wilko for about £1.

You will also need a multimeter to identify the connections on the PCB & a soldering iron.

Identify the 12v positive ( with multimeter ) on the PCB where the wire from the bikes wiring plugs in, the one that becomes live when you operate the brake.
Soldered a red wire to that.

Identify the earth ( Negative ) on the PCB, solder a black wire to that.

Screw the other end of both wires into the connector block.

Then screw all you individule LED wires into the other side of the connector block, obviously red to red & black to black.

Glue the LED's into the lens unit, just a tiny bit of superglue or soft plastics glue.

Test it on the bike, then use some soft plastic clear glue to fix the two halves of the light unit back together.

Mine has not given any problem since.
Title: Re: Back light failiure
Post by: Phmode on July 13, 2018, 05:24:32 pm
How did adding more LED's get round the problem of the driver chip having failed?
Title: Re: Back light failiure
Post by: Philip on July 13, 2018, 05:55:13 pm
They are 12v LED's so don't need a driver.

Connect direct to the 12v coming into the unit from the brake light switch, before it gets to the ( failed ) driver.
Title: Re: Back light failiure
Post by: Sutty on July 13, 2018, 07:33:14 pm
Useful,


Regards.  Mick
Title: Re: Back light failiure
Post by: Phmode on July 13, 2018, 09:34:01 pm
Ah, I see said the blind man who couldn't see at all!

So, the question is, why would BM use LEDs that need a driver in the first place? Canbus? Stupidity? 7-year-old designers?
Title: Re: Back light failiure
Post by: Sutty on July 13, 2018, 11:01:55 pm
Brian , not just BMW, Honda do the same, and I expect all the others do too. But this sounds a great workaround.

 Best regards. Mick
Title: Re: Back light failiure
Post by: Philip on July 14, 2018, 03:56:35 am
" So, the question is, why would BM use LEDs that need a driver in the first place? Canbus? Stupidity? 7-year-old designers? "

No, nothing to do with canbus.

LED's work at about 2.4v & a certain current, depending on the power of the LED.
If you dont limit the current with a driver the LED will just destroy itself.

With single LED's you can do this with just a resistor.

The single 12v LED's have a resistor in their lead to limit the current.

The driver chip on the PCB is a slightly more sophisticated way of controlling the power to the LED array.
But being surface mounted to the PCB & multiple pins, they are difficult to replace without special soldering equipment.
Title: Re: Back light failiure
Post by: sudolea on July 14, 2018, 07:05:33 am
... and the salesman, selling all this after-market sh.t keeps on singing his sales song : "LEDs are known to be much more reliable, sir, as LEDs hardly ever stop working". Of course, he "forgets" to tell you also need a LED driver, which isn't any more reliable than a light bulb ...
Title: Re: Back light failiure
Post by: Blobby on July 14, 2018, 11:55:43 am
The LED's will be fine it's the driver that dies...
I replaced the halogen angel eye bulb on my car with LED's which came with a device to fool the CANBUS system.. I get a warning to say the sidelight isn't working (which it wasn't). I wired the LED straight on to the cable and it works fine..
The light controller outputs 4.5v to the bulb
Title: Re: Back light failiure
Post by: gibbo on July 14, 2018, 04:01:36 pm
Must say I'm not overly impressed with any kind of LED as they seem to be short lived and the over exaggerated claims of thousands of hours life by makers is an absolute joke. Household bulbs, exterior lights all phut out way before their time. Time and time again I've witnessed vehicles with partially lit LED's that probably cost a small fortune to repair. That's the way to save energy cos they don't work.  :D
Title: Re: Back light failiure
Post by: Phmode on July 14, 2018, 04:35:58 pm
But, they are great to drive behind.

Having been through bog standard car and bike headlights (post acetylene) back before alternators became the norm and your lights went out when you slowed down, sealed beam units, halogen bulbs, tungsten halogen, HID Xenon, I can say without a doubt that the LED units in my new car are the cat's whiskers.

Brilliant light, razor sharp cut-off on dip and a great depth and width on main. And none of my house LEDs have gone yet.
Title: Re: Back light failiure
Post by: gibbo on July 15, 2018, 06:42:56 am
I agree that the brilliance of light is an improvement, it's just the shortness of life that needs more R & D.
Title: Re: Back light failiure
Post by: Blobby on July 15, 2018, 10:51:32 am
Must say I'm not overly impressed with any kind of LED as they seem to be short lived and the over exaggerated claims of thousands of hours life by makers is an absolute joke. Household bulbs, exterior lights all phut out way before their time. Time and time again I've witnessed vehicles with partially lit LED's that probably cost a small fortune to repair. That's the way to save energy cos they don't work.  :D
As i said it's not LED's but the power supply/drivers that fail.. Get a decent one of them and the LED should last for ages...
Title: Re: Back light failiure
Post by: gibbo on July 16, 2018, 08:40:04 am
Must say I'm not overly impressed with any kind of LED as they seem to be short lived and the over exaggerated claims of thousands of hours life by makers is an absolute joke. Household bulbs, exterior lights all phut out way before their time. Time and time again I've witnessed vehicles with partially lit LED's that probably cost a small fortune to repair. That's the way to save energy cos they don't work.  :D
As i said it's not LED's but the power supply/drivers that fail.. Get a decent one of them and the LED should last for ages...

Where would you fit a power supply driver in a house then Blobby?
Title: Re: Back light failiure
Post by: Phmode on July 16, 2018, 07:48:31 pm
Nah, they have them up the line in the power stations, millions of the little beggers just waiting to fail on us all  ;D
Title: Re: Back light failiure
Post by: gibbo on July 17, 2018, 05:28:28 am
Nah, they have them up the line in the power stations, millions of the little beggers just waiting to fail on us all  ;D



 ;D ;D ;D Like little transformers then.
Title: Re: Back light failiure
Post by: Phmode on July 17, 2018, 10:38:29 am
Exactement, mon brave!
Title: Re: Back light failiure
Post by: Blobby on July 17, 2018, 11:19:17 pm
My bathroom lights are MR16 12v 3w LED's, replacing 12v 20w halogens.. Unfortunately the halogen power supply would not work on LED's so I got a 240vac to 12v driver from good ol' Banggood (china)..