There are a number of exterior light bulbs around your BMW X3 that require maintenance. The front side marker lights are located in the front fender and work in conjunction with the turn signal light. The front fog light is mounted in the bumper cover and is accessible from behind the wheel well liner.
X3 exterior bulbs are monitored by the Light Module (LM), which also monitors adaptive headlight function (where equipped) and controls instrument panel dimming. LM is also capable of switching lighting functions in case of a fault. For example, in case of a taillight bulb failure, brake light bulbs are used as a substitute.
Bulb monitoring by LM is done both cold and hot (unlit or lit). In cold monitoring, LM sends brief current pulses to unlit bulbs to measure their resistance. The pulses are too short to illuminate the bulbs but serve the purpose of evaluating whether an individual bulb or bulb circuit is defective. In hot monitoring, LM measures the current to individual lit bulbs to determine overload or a break in the circuit.
Keep in mind that when your car was serviced before, parts may have been replaced with different size fasteners used in the replacement. The sizes of the nuts and bolts we give may be different from what you have, so be prepared with different size sockets and wrenches.
Protect your eyes, hands and body from fluids, dust and debris while working on your vehicle. If working with the electrical system, disconnect the battery before beginning. Always catch fluids in appropriate containers and properly dispose of any fluid waste. Recycle parts, packaging and fluids when possible. Never work on your vehicle if you feel the task is beyond your ability.
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Wear gloves when servicing bulbs. Do not let bare skin touch the glass of the bulb.
Fog Light: Using a plastic trim panel tool, lever out the plastic trim (red arrow).
Fog Light: To adjust the height of the light, rotate the 6mm Allen (blue arrow) clockwise to raise beam and counterclockwise to lower beam angle. To remove the fog light, remove the three Phillips head screws (red arrows).
Side Marker Bulb: Press the electrical connector tab (red arrow) to release it from the bulb socket and pull it off. Rotate the bulb socket (blue arrow) counter-clockwise 90 degrees and remove it from the lens. Then pull the bulb out of the socket to replace it. To install, reverse the instructions.