A 2009 8000km Honda GM2 car with a mileage of about 8000km. The owner reflected: when the car appeared before the fog lamp, the front windscreen cleaning motor was always spraying water. After the car: first confirm the failure phenomenon. When the fog lamp is opened, it is found that the front windscreen cleaning motor has been spraying water all the time. According to the analysis of the failure phenomenon, the reasons for the above failure may be as follows: one is the internal fault of the multichannel controller; two is the short circuit of the internal circuit of the combined switch; the three is the short circuit of the front fog lamp and the front window glass cleaning motor line. From the failure phenomenon, the fault involves the two parts of the front fog light system and the front windshield glass wiper / cleaner control system. Because these two systems are independent, we should further confirm the respective working conditions of the two systems and whether there is an impact on each other. After further examination, we found the following phenomenon: the front fog lamp, the left front fog light bright, the right front fog light slightly bright, the front windshield glass cleaning motor water spray work, but the wiper does not move; pull the front windwindow glass cleaner switch, the cleaning motor water spray, the wiper is moved, while left front and right front fog lights are micro The front air window glass cleaner switch and the left front fog light are still bright, but the right front fog lamp is extinguished, the cleaning motor stops the water spray, but the wiper is moving. From the above phenomena, it can be found that the right front fog lamp and the front windscreen cleaning motor work simultaneously, and the wipers and the left front fog lamps work normally. Therefore, there may be a fault between the right front fog lamp and the front windscreen cleaning motor line. Check the circuit diagram and find that the right front fog lamp and the front windscreen cleaning motor share a G451. It is doubted that the circuit breakage of the common bypass line or the bad iron lap causes the right front fog lamp to be connected with the cleaning motor, and the front windshield glass cleaning motor works at the same time when the front fog lamp is lit. Check the right front fog lamp and glass cleaning motor to share the iron point.