What Causes the Abnormal Noise When Turning the Car Key?
2 Answers
There is an issue with the ignition switch. The rear part of the car key is connected to a circular circuit switch, which rotates when the key is turned to connect the circuit (sequentially activating the audio system, the entire vehicle circuit, and the starter motor). When the switch has poor contact, sparks occur along with a squeaking noise. The solution is to remove and replace or repair this switch. Related details are as follows: 1. When the ignition switch is in the "OFF" position: When the key is turned to the "OFF" position, the two contacts in the horizontal position are connected, which means the external wires "white-black wire" and "green wire" are connected. If you measure these two wires with an ohmmeter (Ω setting) at this time, they should show continuity. In the actual vehicle, the connection of these two wires indicates that the entire vehicle's electrical system is shut down, and the ignition system circuit is in a short-circuited state, causing the engine to stop. 2. When the ignition switch is in the "ON" position: When the key is turned to the "ON" position, the two contacts in the horizontal position are connected, which means the external wires "red wire" and "black wire" are connected. If you measure these two wires with an ohmmeter (Ω setting) at this time, they should also show continuity. In the actual vehicle, the connection of the red and black wires indicates that the signal system is activated, and the signal circuit is ready to operate at any time.
There's a strange noise when turning the car key. I've encountered this situation a few times over the years of driving, and it's quite annoying. Common causes include the starter motor possibly aging, where the motor gear and flywheel make a screeching sound upon contact, or insufficient battery power causing abnormal motor rotation. In my case, it was a loose starter that squeaked every time I started the car, and later inspection revealed the screws weren't tightened properly. Issues with the relay in the ignition system can also cause abnormal sounds. If the noise becomes more frequent, it's really necessary to visit a repair shop promptly; otherwise, one day the car might suddenly fail to start, leaving you stranded on the road. When checking, pay attention to the source of the sound, but don't tinker blindly—professional diagnosis by a technician is more reliable, saving money and providing peace of mind. With cars, if details aren't handled properly, the entire driving experience can be ruined, and it might even shorten the lifespan of components.
