A Chevrolet Cruz car with a mileage of about 13 thousand km. The user reflects that the winder of the car does not get out of the wind. After taking the car, the test car found that all the switches or knobs on the air conditioning panel did not respond, connecting GDS2+MDI to detect the warm air, ventilation and air conditioning system control module (K33), and got 1 fault code U1510----LIN bus 1 to lose communication with the device. The devices mentioned here refer to warm air, ventilation and air conditioning control devices, that is, the air conditioning control panel (S34). According to the information, the warm air, ventilation and air conditioning system control module (K33) communicated with other modules through the low speed GM-LAN bus. It maintains and controls the desired air blower, air temperature and air distribution. The positive battery power supply circuit of the battery is supplied to the K33 to maintain the power supply of the erasable memory. If the battery positive power supply circuit is cut off, all K33 stored fault codes and settings will be erased from the erasable memory. The air conditioning control panel (S34) includes all switches used to control the functions of the warm air, ventilation and air conditioning systems. The operator's selected values are transmitted to the K3 through a serial data line to the serial data of a local Internet (LIN) single line network bus between the main control module and the other control modules within a specific subsystem. If serial data communication is lost between any control module on the LAN bus network, the corresponding fault code will be set up. According to the analysis of the fault code and working principle, the possible causes of the above failure are: the power of the warm air, the ventilation and air conditioning system control device power supply or the iron lap abnormality; the LIN 1 line problem; the internal damage of the S34. Check the S34 power, iron and LIN line, all normal; dismantling the S34 examination, found that there is a clear trace of influent oxidation inside, the analysis may be the customer in the sun film or drink drink inadvertently the liquid into it. Troubleshooting: replace the air-conditioning control panel (S34).