Lightbulb warning light 2001 SLK

[Dragster425]

The lightbulb warning light comes on in my Slk 230 auto, as soon as I turn the key in the ignition. It stays on all the time, even though no bulbs seem to be out. Any ideas?

 

[EmilysDad]

is this for light bulbs other than headlights? Try removing & cleaning contacts on your side & tail lights ... on other cars, replacing bulbs with decent brand bulbs has kept the bulb monitoring happy.

 

[Blobcat]

As per above clean the contacts, yr 2000ish Mercedes suffer from corrosion on the contacts that is sufficient to set off the warning

 

[Uncle Benz]

It’s rare, but I’ve seen this type of fault twice before. Both times it required replacement of the fuse board in the end of the drivers side of the dash. If memory serves it comes complete with the light switch. The bulb failure unit is incorporated.
It would be worth pulling both rear lamps first and checking for burned bulb holders though. That is much more common