All of the items were replaced by the mechanic I have been using for my Japanese cars. I realized he was out of his league after $3,000 dollars of replacing items and the light would still come on. He admitted he didn't have the diagnostic computer specific for the car, and was basically guessing what was wrong. He also couldn't find where the central door lock vacuum unit that controls the door locks for the car. At this point I realized I needed to get dealer service or at least find a well-regarded, local independent shop that specializes in Mercedes. He's been there for 26 years. He cleared the computer of all the codes and let me drive the car until the check engine light came on. When it did, he checked the codes, and after looking at the car, determined that there was really nothing wrong with car. I waited in the lobby and kind of watched him diagnose the car. He really examined the vehicle for about 3 hours, and proclaimed that he could tell that the car had been well maintained, and was running absolutely prefectly - except that there was a small oil leak at the front right part of the head gasket, and that a bad wiring harness was causing the check engine light to come on.
Other than the check engine light coming on, the only other symptons the car exhibited are the warning lamp for the airbags came on briefly once and went out, and one time the warning lamp came on for the headlights and quickly went out.
I really don't want to cause damage to the car by not replacing it right away. Are there any techs out there who might be able to give me some good advice....?