"Defective bulb" warning light ..no defective bulbs??

[JVOB]

Hi All

I have just bought a 2001 Fabia Estate, and the defective bulb warning light is on all the time..but all bulbs are OK. I have checked the service sheets that were given to me and I see that over a year ago the service department also noted the fault.. but didn't do anything about it, just said "needs looking into"?

Anyone got any ideas where to start looking please.

Thanks in advance.

JVOB :confused:

[Theresias]

Check the bulb mounting for corrosion.

[ultra_joel88]

Mine came on for some reason when i started the car in -5.00 then went off after 2 minutes

[JVOB]

Ahh.. I see it now that the problem could be that corrosion or damp could earth out a good bulb and allow it to light but still show as open circuit through the line's fuse Hmm.. What an evil little trick to pull. I will report in due course. Thanks all

JVOB

[rigsby]

It is possible that a wrong wattage bulb has been fitted. I have the same problem regularly with M.A.N. trucks. If a 5w bulb has been fitted rather than a 10w or visa versa the computer will flag up a warning. Mght be an idea to check all the bulbs are correct

[cheezemonkhai]

Also LED bulbs will cause it to come on.

Edited 5 February, 2009 by cheezemonkhai

[sms]

i second cheesemonkai first thing that sprang to my mind.

[ming]

Had similar issue and source was high-level brake light. Is that the LED's the guys are referring to, above?

[laldog]

It does not check for an open circuit it only checks the resistance in a given circuit. If that resistance is not within certain parameters then this will flag the warning light on. As above all of these will have an effect but i bet if you really double check all the bulbs physically you will find an odd sized one or a bulb that is near to its end.

[moley]

Had this problem recently, some mornings the bulb warning light would come on. I checked the lights, all working OK. Then one morning the nearside front sidelight aws not working, next time I started the car the sidelight was working OK. It did this on and off for about two weeks. I tested the bulb and it was OK, I replaced the bulb and the problem went away.

As Laldog says you will have to check all the bulbs.