* The AC compressor is cycling on and off. This is normal, and it's what causes the AC to cool the air in your car. However, if the compressor is cycling on and off too frequently, it can cause a noise.
* The AC refrigerant is low. This can also cause the compressor to cycle on and off too frequently, which can lead to a noise.
* There's a problem with the AC fan. The AC fan is responsible for blowing the cool air into your car. If the fan is damaged or not working properly, it can cause a noise.
* There's a problem with the AC condenser. The AC condenser is responsible for dissipating heat from the AC refrigerant. If the condenser is damaged or not working properly, it can cause a noise.
If you're hearing a noise when you turn on the AC in your Lexus RX300, it's important to have it diagnosed by a qualified mechanic. They will be able to identify the source of the noise and recommend the best course of action.
