What Are the Causes of Body Control Module Failure?
3 Answers
The main causes of body control module damage include the following: 1. Excessive current when the brake light bulb or position light bulb filament burns out; 2. The filament shorting to the position light filament when it burns out; 3. Failing to replace a damaged brake light bulb on one side in time; 4. Damage to the internal chip of the body control module due to car modifications. The symptoms of body control module failure are as follows: 1. For automatic transmission models: Trunk cannot open, car key cannot be removed, P gear is locked, brake lights do not illuminate (high-mounted brake light functions normally), windshield washer does not work, cigarette lighter does not work. (Including atypical faults: automatic door locking failure while driving, central locking failure, abnormal horn operation, abnormal wiper operation, starting failure, etc.). 2. For manual transmission models: Trunk cannot open, position lights do not illuminate, brake lights do not illuminate (high-mounted brake light functions normally), windshield washer does not work, cigarette lighter does not work. (Including atypical faults: automatic door locking failure while driving, central locking failure, abnormal horn operation, abnormal wiper operation, starting failure, etc.).
I think there are quite a few reasons for body control module failures. Based on my own driving experience, the most common ones are electrical issues, such as unstable voltage or short circuits. Last time my car's windows suddenly stopped working, it was due to aging wiring causing module overload. Software problems are also a factor—if bugs aren't fixed after a system update, malfunctions can occur. Environmental factors like water intrusion or high temperatures can affect component functionality as well. Messy wiring during car modifications can also damage the module, so it's important to regularly check the wiring and watertightness to prevent small issues from becoming major problems.
As someone with years of experience in automotive repair, common sources of faults include circuit short circuits and wire corrosion. When the voltage is too high, fuse protection failure can damage modules; physical damage such as impacts or water ingress is also common, especially after the vehicle gets damp; component aging like relay wear can also cause control failures. It is recommended to test voltage and ground wires during every maintenance session, fixing any issues early to prevent them from spreading to other systems, ensuring safe driving.
