Any LED bulb upgraders come across this before...?

I've just replaced my sidelight LED bulbs with a set from fizzmo.co.uk. The supplier states they are CANBUS error free.

With the light switch set to the off position my sidelights flash very briefly 5/6 times every time the ignition is turned on. I have factory fit xenons if that has any influence. Although the bulbs do not show as an error on the CANBUS system there is clearly a problem..... or is my car trying to tell me something in morse code?

I've emailed the supplier to see what they can come up with but any experiences here could prove useful in "negotiations"

Isn't that flashing just caused by the cold lamp diagnostics? Basically how the car decides if the bulb is out or not by testing it. I believe this can only be seen on LED bulbs as the switch on time is much shorter than the traditional bulbs,

I seem to remember Brimma saying he noticed this when he put the Dectane LED tail lights in, although I would have thought they would only flash once rather than 5/6 times, but maybe not.

I have known some to do this. Try rotating the LED and fitting again as some will only work one way round in the connector.

Hope that makes sense.

Same here. CANBUS friendly W5W LEDs. When turning the ignition on, my LED sidelights will do the 5-6 flashing thing. Been told it's indeed the CANBUS system test that causes the LEDs to do this. Doesn't bother me.

Edited 3 December, 201213 yr by Too Tall

Probably not that good for the LEDs, or probably for CANBUS in the longer term. I would turn off lamp diagnosis in VCDS, if I were using LED bulbs.

Thanks for the advice peeps. I'll give the rotation a shot if the supplier doesn't come up with a definite solution. Certainly can't imagine its doing the bulbs much good!

Normal, haven´t lost one so far.(sidelights,DRL,Dectane taillights including reverse)

LEDs dont care about constant switching on/off like a normal bulb. Think of the Hifi gear that have LED level indicators, that go on for years without fault despite constantly flashing on/off.

Probably not that good for the LEDs, or probably for CANBUS in the longer term. I would turn off lamp diagnosis in VCDS, if I were using LED bulbs.

It happens with normal bulbs too, you just don't see it as the flash isn't long enough to notice, so won't harm the CANBUS

Received a VERY comprehensive reply from the supplier...

To explain whats going on here:

Most canbus systems pulse power to bulbs and measure the returned reading to test bulbs - whether they are working or not. This happens at different intervals or in some cars every set period of time. In your vehicle one of the times this happens is when you turn the ignition.

Normally when this pulse is sent around the car, its not enough power to light up a normal filament bulb - the current just passes through. With Led bulbs they require such a small amount of power to work, they can light up on this - in fact you can light up an led on many household power supplies like a smoke alarm battery for example.

Now, canbus led bulbs have load resistors built in to prevent errors appearing when the bulbs are lit up and working - they imitate a normal bulb when the car lights are on . However these bulbs are not immune to lower power supply in the circuit to which they can be lit up on, the canbus function of the bulb is not made to deal with this.

This is actually a common occurrence and should not affect the life of the bulb - in fact many German vehicles do this, some VAG cars and some BMW. Most owners never realise as they are in the car when it happens however there is word of it around many forums around the internet. One very quick search popped up a thread, see post 18/19:

www.briskoda.net/forums/topic/153065-led-front-side-light-help/

Our auction advises:

• *ATTENTION: Some advanced canbus/bulb error systems may cause the lights to blink, turn off or still give an error on the dash. Such cars require additional load resistors to ensure normal working bulbs, they can be found here (most 2006 onwards VW/Audi/Skoda/Seat/VW group cars may require these, other car brands vary)
  

</p>

The load resistors advised in the auction may solve this issue however we cannot guarantee this as VAG cars are actually notorious for having the most difficult canbus systems on the market (hence our auctions for canbus bulbs generally only mention VAG cars requiring additional load resistors).

In light of the above, if you would like to try the plug and play resistors advised, then see here:

http://www.ebay.co.uk/itm/2-x-LED-501-T10-W5W-WEDGE-CANBUS-NO-ERROR-LOAD-RESISTOR-/300590337115?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item45fc948c5b

If you would not like to use these resistors then we can accept these back for a refund and would like to apologise for any inconvenience this may have caused.

If you would like to keep these for use in the sidelights, then thank you for your understanding. Also remember the bulbs can be used in all w5w applications canbus or not so they can be used in other locations on the car too.

Received a VERY comprehensive reply from the supplier...

To explain whats going on here:

Most canbus systems pulse power to bulbs and measure the returned reading to test bulbs - whether they are working or not. This happens at different intervals or in some cars every set period of time. In your vehicle one of the times this happens is when you turn the ignition.

Normally when this pulse is sent around the car, its not enough power to light up a normal filament bulb - the current just passes through. With Led bulbs they require such a small amount of power to work, they can light up on this - in fact you can light up an led on many household power supplies like a smoke alarm battery for example.

Now, canbus led bulbs have load resistors built in to prevent errors appearing when the bulbs are lit up and working - they imitate a normal bulb when the car lights are on . However these bulbs are not immune to lower power supply in the circuit to which they can be lit up on, the canbus function of the bulb is not made to deal with this.

This is actually a common occurrence and should not affect the life of the bulb - in fact many German vehicles do this, some VAG cars and some BMW. Most owners never realise as they are in the car when it happens however there is word of it around many forums around the internet. One very quick search popped up a thread, see post 18/19:

www.briskoda.net/forums/topic/153065-led-front-side-light-help/

Our auction advises:

• *ATTENTION: Some advanced canbus/bulb error systems may cause the lights to blink, turn off or still give an error on the dash. Such cars require additional load resistors to ensure normal working bulbs, they can be found here (most 2006 onwards VW/Audi/Skoda/Seat/VW group cars may require these, other car brands vary)
  

</p>

The load resistors advised in the auction may solve this issue however we cannot guarantee this as VAG cars are actually notorious for having the most difficult canbus systems on the market (hence our auctions for canbus bulbs generally only mention VAG cars requiring additional load resistors).

In light of the above, if you would like to try the plug and play resistors advised, then see here:

http://www.ebay.co.uk/itm/2-x-LED-501-T10-W5W-WEDGE-CANBUS-NO-ERROR-LOAD-RESISTOR-/300590337115?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item45fc948c5b

If you would not like to use these resistors then we can accept these back for a refund and would like to apologise for any inconvenience this may have caused.

If you would like to keep these for use in the sidelights, then thank you for your understanding. Also remember the bulbs can be used in all w5w applications canbus or not so they can be used in other locations on the car too.

Hats off to them. Good stuff.

Not sidelights but this video showing LED's used for the front fog / cornering light function shows how sometimes it's just best to leave things OEM...