Blown Bulb Warning

[Cornishexpat]

Whenever I start my car (2006 octavia 4x4 FSI) I get the Blown Bulb warning lamp on the dash. I've checked all the lights and they work, and strangely turning on full beam for 5 seconds clears the fault until the ignition is turned off and on again.

 

Any ideas?

[Phil-E]

Sounds like a dodgy bulb.

 

It will be working but will be about to go. If you have diagnostics (VCDS) then it can tell you exactly which bulb is causing the problem.

 

Phil

[silver1011]

When checking the lights is the warning still on on the dash?

 

As Phil mentions as bulbs get weak (just before they blow) they can trigger the dash warning.

 

This is why Maxidot is useful as it calls out exactly which bulb is causing the issue rather than just the orange indicator in the dash cluster.

 

A bulb that is often missed during the visual checks are the two number plate lights, have you checked these?

 

The W3W bulbs that make up the 'C' shape on the tail/night lights often blow and again are easily missed but I don't believe these are monitored by the blown-bulb warning system.

[Cornishexpat]

Thanks for the suggestions. My cheap and cheerful eBay fault code reader doesn't show anything for the bulbs. I didn't check the number-plate lights so will have another look.

Would I be right in saying that it's just a case of waiting 'til the bulb blows If I can't get hold of VCDS?

Just seems strange that 5 seconds of full beam seems to clear the issue

[silver1011]

The extra load on the electrical system required to power the main beam bulbs might be enough to overcome the higher resistance of the failing bulb, thius cancelling the blown-bulb warning...

[Guest]

Power up all lights with the help of an assistant to depress the brake pedal and go around the car giving each light cluster a thump and look for a failure.

Don't forget hazard warning, fogs and reverse.

[JD52]

The number plate light is a sneaky one as the metal prongs that the bulb fits in can bend causing an intermittent fault.

[Cornishexpat]

Just changed a rear number plate bulb and it cleared the issue until I turned the ignition off then on again. Number plate lights still worked so I might have to get the girlfriend to press the brakes whilst I start whacking the lights!

[silver1011]

So one of the number plates bulbs had blown?

 

But despite replacing it the on-dash warning remains?

[Cornishexpat]

Yes, the fault still remained after changing the blown number plate bulb.

Had the car serviced by Kennys VW in Inverness and they said the fault code is for the Nearside headlight. They seemed a bit perplexed that the bulb still lit up.

[Guest]

I've had flaky bulbs before which flagged up the blown bulb warning yet looked OK and lit up when connected to an alternative power source.

The filament must've been less than ideal or the bulb connector itself may need cleaned/reconnected to make a good contact.

[Cornishexpat]

Replaced the Main and dipped beam bulbs for Halfords 120% ones and the warnings gone. I can also see more than 10ft in front of me!