Hi, We just picked up an Alphard camper yesterday, it still has the original head unit. The first thing i did was tune the radio to the frequency of my aukey bluetooth fm transmitter. The fm transmitter is tuned to 87.5 and works perfectly. A good solution unitl i decide what to do with the OEM HU.
I bought it from Amazon a couple of years ago, does not seem to be available anymore but plenty of others on there