Electrics: Bulb Failure Dipped Beam (but the bulb is fine)

[SED5]

Hi all, I have had a similar problem with my passenger side (rhd) xenon dipped bulb failing intermitantly ........then the problem went away and every thing was fine.... just had the car serviced and when asked if I had any issues I explained that I had light bulb failure but that it had been ok for quite a few months ......would you believe it driving home from the garage the bulb failure started again !!!! I am curious surely every time the bulb fails it generates a fault code and on the service check list it was ticked to say they had been checked but no mention was made of this when I picked up the car ........I have removed the light unit and checked the connections and all seems fine ......I must say Roy's theory of the filiment being the cause is plausible as on a few occasions I have noticed the bulb failing after travelling over a rut or pothole in the road .........anyone know of a best price for Xenon bulbs ??
Thanks
Mike

[400-ascona]

Buy a well known brand like Osram etc. Anything from £40 to £90.

I would Disconnect all the plugs first and spay in a little WD40 in each. Don't forget the one that is clipped to the bodywork, which is designed as a quick disconnect to save you having to take out all the bulb connectors when you remove the light. If this makes no difference, then go for a new bulb.

[RoyMacDonald]

Originally Posted by SED5

I must say Roy's theory of the filiment being the cause is plausible as on a few occasions I have noticed the bulb failing after travelling over a rut or pothole in the road .........anyone know of a best price for Xenon bulbs ??
Thanks
Mike

I was talking about halogen bulbs and you can often see the filament waving around if you take the bulb out and move it about.

Xenons don't have a filament, as the light is generated in a tiny cloud of plasma around the electrodes. More likely to be a contact issue with the plugs or wireing.

[owenfackrell]

Just to echo what Roy says above. Xenons are a gas discharge bulb and they create an electrical arc which gives the light. typical they have a starting voltage of 70k which drops to 30k ish when struck. You can normal notice that on turning them on that you get a flicker and then the light get brighter. When buying replacements watch what colour you go for standard is 4700k the higher the number the blue it is but the less visible light it produces (this is the light that reflects back allowing you to see). The blue light effect you see on high end BMW, Mercs and the latest XC90 is done with the projector headlight.

[XC90caravanpuller]

Originally Posted by RoyMacDonald

I was talking about halogen bulbs and you can often see the filament waving around if you take the bulb out and move it about.

Xenons don't have a filament, as the light is generated in a tiny cloud of plasma around the electrodes. More likely to be a contact issue with the plugs or wireing.

Wow this gets complicated doesn't it. (tiny cloud of plasma )
I have recently had this problem and the car is now in with the local Volvo specialist Amber Garage, Southwick, for service and MOT.
I'll let you know what transpires.
Are you saying that Bi xenons don't wear out?
what does the "Bi" bit stand for /mean?
Thanks
Ross

[RoyMacDonald]

Originally Posted by XC90caravanpuller

Wow this gets complicated doesn't it. (tiny cloud of plasma )
what does the "Bi" bit stand for /mean?
Thanks
Ross

The size of a pin head.

Bi = two?

[owenfackrell]

My understanding of the bi-xenon lights is that they also have a xenon light for the main beam.

[XC90caravanpuller]

Originally Posted by RoyMacDonald

The size of a pin head.

Bi = two?

Thanks, I am now the proud owner of a £103 new bulb that works, so don't know if all the other possibilities are yet to transpire.
12 month service with oils, filters n new wiper blades MOT (+bulb) Inc VAT 17.5% £623 .(Gulp/wince)
Xmas will now be a sausage on a stick and a candle.

[newrangerfamily]

IndyVolvo

Can you tel me if you fixed the problem - if so what was the fix?

Many tanks

[Loctite85]

Hi gents,

My 2003, D5 AWD currently has the same “bulb failure dipped beam” message. Currently, when I switch to DLR on the switch, the RH unit comes on dipped, the LH unit, only turns on the DLR.
When I swap the head light units over, complete with loom, the same happens with the same units. I.e: putting the RH unit in the left socket, dipped comes on and the LH unit in the RH socket, only the DLR comes on.
Now, my expertise on electrics/electronics is very limited, but enough to survive, so I’m concluding that the fault lies within either the loom too the RH unit or within it.

Just wondering if anybody else has experienced this and what others my think.
TIA