"CHECK LAMPS" and lights that wont go off / 2001 C240

[Herr Leber]

My 2001 C240 automatic light system is acting weird. Occasionally I get a "CHECK LAMPS" warning on the dash, but all lamps appear to be working both inside and out.

Also , with the headlight switch on auto, on one occasion the lights didnt go out when I parked the car in an indoor shopping center parking lot. Yikes! Fortunatley I was in and out.

Intermittent troubles are frustrating. Any thoughts fellas?

[joe p]

I replaced a few rear sams on those when they first came out. Also check the version coding in IC, they'll forget what country they are in occassionally.




Joe

[Herr Leber]

Thanks for the reply Joe.

You went over my head. Whats a SAM and whats IC?

[Gilly]

A SAM is a "System Activation Module". What it means, in laymans terms, is a computer that controls various functions of the car. Usually if you think of a computer in a car, you think of like the engine control unit, something that has a definite job to do, like run the engine. These SAM's have various "little" tasks to do, not just one "big" job. Some of them may run a few different lights, and maybe work part of the door locks, and pop the trunk lid for example.
But here's my impression:
First, usually the dash on a 203 chassis will not only tell you that a light is inop, it will also usually give you some indication of WHICH light is out. Aren't you getting some type of clue as to which one it is? It may be rather cryptic in nature, like "LR Tail" or something like that.
Also, this is really trick, but it also has whats called "substitute lighting". What it may do is for example if the Left tail light is out, it will switch off BOTH of the "normal" tail light bulbs and instead use BOTh of the brake light bulbs at a reduced brightness to mimic a pair of tail lights. They won't be in the "correct" place that the tail lights are supposed to be in, but it will look "normal" to anyone not familiar with the tail lights on your car. So study that a little. If the tail lights are at the top position of the rear lenses, that's not right, it's using substitute lighting.
There were just a real rash od bulb outtages on 203 chassis for the first year or two. On the tail lights they came out with an adapter harness for the tail lights, your dealer should be aware of this, there is a bulletin on it.
Also on the FRONT park/turn signals, there is also a kit which should be installed which modifies the harness, there is also a bulletin on this problem as well for the earlier C Class cars.
BOTH of these bulletins deal with inop lights, the one for the rear deals with burning out bulbs rapidly, and the front kit just deals with the bulbs not working due to a bad ground connection.
They are both quite common occurances on the 203 chassis C Class.

Gilly

ps IC is instrument cluster