I have a 1999 C-230 and the warning light on the dash indicating there is a bulb out has come on. I have checked every bulb on the entire car and they are all good. Any suggestions? Thanks

 

Check the third brake lamp??
Check Back up lamps??

You can isolate the offending circuit as the indicator warning will come on after that circuit is turned on.
So, take note of what you just turned on when the warning appears..

The warning also will get tripped if you are using different brand lamps in a pair circuit [ like different parking lamps, etc...

 

I have checked all those lights and I havent replaced any lights....it just came on and is always on...it gets brighter when I push the brake pedal but none of the brake lights are out I have checked them all individually....I dont know what to do....

 

You could have a bad brake lamp filiment. It still lights,but could be shorted or loose in the socket.
I would change them as a pair ..

 

I have the same problem, or had. It usually originates with the rear fog lamp bulb, bottom left side right bulb. Why? the bulb has two filaments, as does the bulb on the right side with would be the lower bulb, same number also. If either bulb are not seated correctly, one of two things happens, you get both filaments on both sides or they won't work, the bulbs on the right side needs to be seated with the shorter nib facing you and turned counter clock. on the left side the shorter nib facing you and turn clockwise. Before you go all thru this tap on the right parking like holder, lower bulb closest to you, This work for me the other day. Another problem area that will set off the check bulb, is the trunk, I found if I don't close the trunk with a sold tud, I will get a check bulb now a then, it is probably the switch which is tied into the same wire harness as all the rear lights.

Also, the bulb holder in these cars is junk, I disconnected both of them and cleaned them up use a sanding pencil to the clean the contact; and with double contacts, I noticed a few were touching and that will automatically trigger a check light bulb, take the key out of the ignition and be careful you don't ground against anything. I wrapped my sending pencil in duct tape as the handle is metal. Also, use Mercedes of Sylvania replacement bulbs, exact number also. A freind with a S Class replaced his stop light with a generic bulb and it ruined the cruise control $1700 to fix. Finally always us dielectric grease on the bulb stems. When I first replaced a rear bulb, corrosion was the culprit.

 

Check with a dealer .. these lamp sockets have been up-graded and I think there is a free TSB on it...

 

Trouble code P0306 ideas?? Pug wires both??

 

I have the same issue, at times the warning light appears but then it goes away. you might want to get your fuses checked.