NTRODUCTION A common problem experienced by BMW X5 owners is a “Check Rear Lamp”, or “Check Brake Lamp” message from the Lighting Control Module. Many owners have found that their rear lights were not burned out, and after removing and re-inserting the lamps, the problem is solved briefly, but returns. The problem is a faulty rear lamp assembly. This can be cured by replacing the entire rear lamp assembly at considerable cost (if it is not under warranty). The following write up addresses a common manifestation of the problem, and how to repair the rear lamp assembly. Please follow the following steps to diagnose your rear lamp assembly and repair it. BACKGROUND INORMATION The BMW X5 uses a sophisticated Lighting Control Module (LCM), which controls all lamp functions in the vehicle. This computer can detect a burned out lamp and alert the driver through the instrument panel display. In order to do this, the LCM sends signals to the lamps continuously, monitoring the connections and resistance of the lamp filaments. A poor connection in a lamp circuit can appear to be a faulty lamp. This is the common situation that X5 owners may experience.