This guide provides a step-by-step walkthrough for repairing a BMW light control module (LCM). This repair addresses a common issue of a stuck high beam, potentially saving you hundreds of dollars compared to dealer repair costs. This DIY solution involves replacing specific chips on the LCM’s circuit board.
Locating and Removing the LCM
First, disconnect the negative battery terminal to prevent accidental electrical shorts and avoid potential key fob issues with the electronically opened trunk. Next, access the LCM located behind the passenger-side kick panel. Gently but firmly pull the kick panel cover to release it.
After removing the cover, pull back the carpet to expose the LCM. You’ll see one 8mm bolt securing the module and a clip at the top. Use an 8mm socket to remove the bolt. Disconnect the three plugs connected to the LCM. Carefully detach the LCM and take it to your workspace.
Disassembling the LCM
Gently pry open all the clips on the plastic cover and separate it from the module. To remove the circuit board, slide the board and plugs back while pressing down on the sides of the center plug. Small tension clips secure components on the board. Use a small screwdriver to twist these clips upwards and then pull them out by hand.
Replacing the Faulty Chip
Once the tension clips are removed, carefully lean the chips away from the heat sink, as they hold it in place. Unscrew the five T-9 Torx screws securing the heat sink to the circuit board. Then, carefully pull the heat sink free. You will need to desolder and replace the faulty chip. Resources for identifying the specific chip location related to headlight issues, as well as soldering techniques, can be found online.
Reassembly and Installation
After replacing the chip, reassemble the LCM by following the disassembly steps in reverse order. Ensure all connections are secure and the module is properly fastened. Reconnect the negative battery terminal.
This repair requires basic soldering skills and tools, including a soldering iron, solder, desoldering braid or gun, a T-9 Torx bit, an 8mm socket, and a grounding wrist strap. The total repair time is approximately 2.5 hours. The cost of replacement chips and necessary equipment is significantly less than the price of a new LCM from a dealer. Remember to consult additional online resources for detailed instructions and visuals before attempting this repair.
