Multi Function Display: Not working, due to new head unit?

[tiny2009]

Picked up the JZX110 on the weekend and it has one of those GPS/TV/Aircon control touch screen things. Problem is this does not work, all I can do is change the background picture and contrast... not too fussed about the GPS and TV but it would be nice to know what the aircon is set on.

I have heard that its common for these units to be interactive with stereos. Anyone know if this is the case? The yard had a new stereo put in after it arrived in the country (think the previous one might have been taxed in transit?).

If I am unable to track down a factory stereo what other options are there? Can this bit of kit be modified or bypassed at all? Can these displays be used for much else or am I stuck with a fancy bunch of nothing?