w202 faulty light warning

[design guru]

I have a w202 98' C240 and the warning light for the 'lights' is constantly on and I have checked all the lights and they work fine.

Any thoughts why this could be?

 

[andy27168]

Hi,
When does the warning light come on? as this will give you an indication on what is putting it on.
Does it come when you just touch the brake pedal (light switch in the off position), this would be the brake light bulb circuit at fault somewhere.
Does it come on with the light switch on the first click, in this case it will be front side lights (x2), rear side lights (x4), number plate lights (x2).
Does it come on with the light switch on the second click, in this case it will be either the front dipped beams (x2).
Once you have established when it comes on you can then look at those circuits specifically, though normally it will be one or other of the rear light bulb holder assemblies, if of course all the bulbs are ok, clean, and of the right wattage

 

[Shude]

typically it's because a bulb is falling out of it's socket or is *about* to pop.

 

[Steve Holland]

Also check your earth feeds as this can also leave an open circuit and show up as a faulty bulb/light cluster.

 

[design guru]

Hi,
When does the warning light come on? as this will give you an indication on what is putting it on.
Does it come when you just touch the brake pedal (light switch in the off position), this would be the brake light bulb circuit at fault somewhere.

This is exactly when the warning light comes on. Thanks for the starting point, I'll look into this further.