Telling me I have a bulb malfunction but I don't think I have

MBDevotee

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Dreaming of a CL55k - one day maybe....
Hiya,

Whenever I turn on the Lights on my W208 CLK (Xenon option) the dash shows a faulty bulb, It happens whether I put side or main lights on.

I have walked around and all the lights appear to be working fine.

I knew someone with the same problem with another merc and it was the switch itself, however I wondered if it's safe to assume that or whether I need to get it checked out by a merc dealer or good indi?
 

Dec

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Perhaps the rear fog light on drivers side, it only comes on when switched on separately from the rest of the lights, just a suggestion, don’t know your car but on mine there are 2 extra light to the rear, in other words double break lights or double rear lights, not sure which. Other than I haven’t a clue.

Dec
 

brianbrian

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Make sure bulbs are making a good clean contact even though they are working this is normally the problem.Hope this helps
 

MB TECH WARRINGTON

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there are 2 bulbs per side on the rear on 208 models, both bulbs are sidelight operated, check that all 4 are working:rolleyes:
 

jimsinessex

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2008 W209 CLK 320CDI Coupe
Hiya,

Whenever I turn on the Lights on my W208 CLK (Xenon option) the dash shows a faulty bulb, It happens whether I put side or main lights on.

I have walked around and all the lights appear to be working fine.

I knew someone with the same problem with another merc and it was the switch itself, however I wondered if it's safe to assume that or whether I need to get it checked out by a merc dealer or good indi?

Switch ingnition on (do NOT touch brake pedal), switch sidelights on ONLY. If bulb failure warning comes up it is definitely a side light or rear number plate bulb and none of the others.
Have you replaced any bulbs recently as non-MB sourced bulbs sometimes trigger the failure warning. In particular check the wattage of the rear combined brake/sidelight bulbs as it should be 21/4W and not the more usual 21/5W bulb. This caught me out once!

Jim
 

LYNALL

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Only stuck 5 watt in wifes 203 with no problems, when they initially failed the car said it was using the rear fog as a temporary rear light.



Lynall
 

jimsinessex

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Only stuck 5 watt in wifes 203 with no problems, when they initially failed the car said it was using the rear fog as a temporary rear light.
Lynall

On the W208 it is only the dual filament brake/sidelight that is 4W, the other single filament real sidelight is 5W. That's where the confusion arises.

Jim
 

jberks

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The system monitors current usage. So, as above, it's either wrong wattage bulbs, or dirty contacts causing excessive resistance. Do note MB bulbs use an offset pin design - as against opposite pins on a 'normal' bulb.
Assuming the bulbs are correct then its the contacts - almost always is, so work around the bulb holders, including the number plate light and clean them up.
 

jeremytaylor

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I used to get these blown bulb messages regularly in my C270CDI Estate. It was invariably dirty contacts that was the problem.
 
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