I have a 2006 R350. every once and awhile I get a message light for "light out back right (Substitute Bulb on)", then another one for left, (Substitute Bulb on), Sometimes I get all the above but this time it says that the license blub right out ,then one for a "Tall Light", whatever that is. But all back Blubs are on. I Reset and for weeks "No Message" at all about a problem with the Back array. This usually happens when my wife drives the car. Then when I go out to restart the car to see what's wrong no messages everythings OK!! I did purchase the 4 year, 50,000 MB warranty when I purchased the pre-owned R. You know how the Dealers are "It wouldn't happened while it was here, we can't find anything wrong". Any ideas?

 

Replace the bulb. Even if it isn't burnt out, it could be creating enough resistance to trigger the warning. I had this happen to license plate lights on my old C-Class. I'd get out and check only to find both bulbs lit. Replacing the bulb anyway fixed the warning.

 

More than likely it's the wiring harness/connector(s). Mine had same problem to an extent, then it just started burning out bulbs, one right after the other within hours of replacing. Took it to dealer, they said it was a harness/connector issue. Replaced entire harness, w/ new updated one (there should be a TSB from what i gathered), in 1 day. Have not had a problem in the 15 months since.

 

Yep, same here.

Intermittent issues and just got bad bulbs. Changed them out and all the issues went away.