When you’re driving, hundreds of components have to work in synchrony in order for your car to run smoothly. If one of those pieces begins to wear out, it’s usually a clear signal that the vehicle is going to have trouble. That’s why it’s important to know what to look for when the car making humming noise when off occurs.
This type of sound could be coming from any number of different systems in your vehicle, but the first thing to figure out is where the hum is coming from. A humming noise while the car is running typically comes from parts that move or spin while your vehicle is in motion, so it’s likely that it’s related to the drive train. This includes the transmission, drive axles, carrier bearings and wheel bearings. These parts tend to make a humming sound when they’re beginning to wear out.
A humming noise when the car is off but still turned on might be caused by the alternator, which is responsible for charging your vehicle’s battery and supplying power to the engine. Early bearing failure in the alternator can cause it to start humming or even grinding. A qualified technician can diagnose the issue and recommend the best course of action.
A humming noise while the car is off and the air conditioning system is turned on might be caused by a damaged compressor. The job of the compressor is to convert liquid refrigerant into a gas that can be expelled by the air conditioner to cool the vehicle.