In the past I've thrown out the idea that it could be the xenon lights, which require a ballast. A ballast is a device that increases voltages to the levels that some types of light bulbs need to work. In the past transformers were used but more recently they have been replaced by electronic ones. One difference between the two are the frequency of the ac voltage that they use. Electronic ballasts operate at much higher frequencies, so instead of hearing a buzz or hum we now hear high pitch noise. The research I've done has indicated that electronic ballasts in cars work at around 450hz, which isn't close to the sound we're hearing. But it could be possible that the ballasts used in some Nissans and Infinitis use a much higher frequency. I'm not saying this is the problem, but it's a possibility and I'll throw the idea out there.
|