Electrical › Lighting system › Diagnosis
踩下制动踏板，制动灯都不亮 · T00611516

 When I press the brake pedal, the brake lights don't come on.踩下制动踏板，制动灯都不亮

①General inspection一般检查
1. Power status "OFF".电源状态“OFF”。
2. Connect the diagnostic tool.连接诊断仪。
3. Power status "ON".电源状态“ON”。
4. Use a diagnostic tool to read the fault code and check whether there is a fault.用诊断仪读取故障码，检查是否存在故障。
Check if there is a fault code?检查是否存在故障码？
Yes → Troubleshoot related faults according to the fault code.是>>根据故障码排除相关故障。
No → Go to step 2.否>>去步骤2。
②Check the wiring harness connector检查线束接插件
1. Power state is "OFF", disconnect the negative terminal of the 12V battery.电源状态“OFF”，断开蓄电池负极。
2. Check the integrated body control module and brake switch wiring harness for damage, breakage, etc.检查集成式车身控制模块和制动开关线束是否存在损坏、断裂等现象。
3. Check whether the integrated body control module and the brake switch harness connector are connected or damaged.检查集成式车身控制模块和制动开关线束接插件是否存在虚接、损坏等现象。
Are the test results normal?检查结果是否正常？
Yes → Go to step 3.是>>去步骤3。
No → Repair or replace the faulty wiring harness or connector.否>>维修或更换故障线束或接插件。
③Check the installation position of the brake switch检查制动开关的安装位置
1. Check whether the installation position of the brake switch meets the requirements.检查制动开关的安装位置是否符合要求。
Are the test results normal?检查结果是否正常？
Yes → Go to step 4.是>>去步骤4。
No → Reinstall as required.否>>按要求重新安装。
④Check fuse检查保险丝
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1. Power state is "OFF", disconnect the negative terminal of the 12V battery.电源状态“OFF”，断开蓄电池负极。
2. Check whether the fuse IF20 in the electrical box on the instrument panel is normal.检查仪表板电器盒中保险丝IF20是否正常。
IF20：7.5A
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c. Check whether the fuse EF18 in the electrical box in the front compartment is normal.c.检查前舱电器盒中保险丝EF18是否正常。
EF18：7.5A
Are the test results normal?检查结果是否正常？
Yes → Go to step 5.是>>去步骤5。
No → Replace the fuse with the same specification.否>>更换相同规格保险丝。
⑤Check brake switch 12V battery power harness检查制动开关蓄电池电源线束
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1. Power state is "OFF", disconnect the negative terminal of the 12V battery.电源状态“OFF”，断开蓄电池负极。
2. Disconnect brake switch harness connector FB52.断开制动开关线束接插件FB52。
3. Connect the negative terminal of the 12V battery.连接蓄电池负极。
4. Use a digital multimeter to measure the voltage between pin 2 of FB52 and ground.用数字万用表测量FB52的2号针脚与接地之间的电压。
Standard voltage value: about 12.5V标准电压值：约12.5V
Are the test results normal?检查结果是否正常？
Yes → Go to step 6.是>>去步骤6。
No → Repair or replace the brake switch battery power harness.否>>维修或更换制动开关蓄电池电源线束。
⑥Check the brake switch IG1 power harness检查制动开关IG1电源线束
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1. Power state is "OFF", disconnect the negative terminal of the 12V battery.电源状态“OFF”，断开蓄电池负极。
2. Disconnect brake switch harness connector FB52.断开制动开关线束接插件FB52。
3. Connect the negative terminal of the 12V battery and the power status is "ON".连接蓄电池负极，电源状态“ON”。
4. Use a digital multimeter to measure the voltage between pin 3 of FB52 and ground.用数字万用表测量FB52的3号针脚与接地之间的电压。
Standard voltage value: about 14V标准电压值：约14V
Are the test results normal?检查结果是否正常？
Yes → Go to step 7.是>>去步骤7。
No → Repair or replace the brake switch IG1 power harness.否>>维修或更换制动开关IG1电源线束。
⑦Check the brake switch signal harness检查制动开关信号线束
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1. Power state is "OFF", disconnect the negative terminal of the 12V battery.电源状态“OFF”，断开蓄电池负极。
2. Disconnect brake switch harness connector FB52 and integrated body control module harness connector FB51/BD57.断开制动开关线束接插件FB52与集成式车身控制模块线束接插件FB51/BD57。
3. Use a digital multimeter to measure the resistance between pin 4 of FB52 and pin 45 of FB51.用数字万用表测量FB52的4号针脚与FB51的45号针脚之间的电阻。
Standard resistance value: <1标准电阻值：＜1 Ω
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d. Use a digital multimeter to measure the resistance between pin 1 of FB52 and pin 5 of BD57.d.用数字万用表测量FB52的1号针脚与BD57的5号针脚之间的电阻。
Standard resistance value: <1标准电阻值：＜1 Ω
Are the test results normal?检查结果是否正常？
Yes → Go to step 8.是>>去步骤8。
No → Repair or replace the brake switch signal harness.否>>维修或更换制动开关信号线束。
⑧Replace brake switch更换制动开关
1. Replace the brake switch and check whether the fault is eliminated.更换制动开关，检查故障是否排除。
Are the test results normal?检查结果是否正常？
Yes → Fault resolved.是>>故障排除。
No → Go to step 9.否>>去步骤9。
⑨Replacing the integrated body control module更换集成式车身控制模块
1. Replace the integrated body control module and check whether the fault is eliminated.更换集成式车身控制模块，检查故障是否排除。
Are the test results normal?检查结果是否正常？
Yes → Fault resolved.是>>故障排除。
No → Find the cause from other fault symptoms.否>>从其他故障现象查找原因。
  Caution:注意：
♦  After replacing the integrated body control module, you need to use a diagnostic tool to recalibrate the integrated body control module.更换集成式车身控制模块后，需用诊断仪对集成式车身控制模块重新标定。