The only thing I hear when the wipers are working is a very soft clicking noise below the dash which corresponds to the wipers. To me it does sound like an electronic relay or message node. Just to be safe, you should let your service department hear it the next time your at the dealership. If its something abnormal, please post your findings.
I have a new 2016 QX60, and just noticed this clicking noise without wipers on. Seems to be coming from passenger side front dashboard. I will test further but I believe it may be appearing with on and off application of the brakes? I'll contact my dealer too. Might be related to the accident prevention systems?