95 Nissan Cedric Control Panel Issues:

I have a 95 Nissan Cedric that has a control panel located in the dash. This control panel operates the AC, heater, Radio, GPS, etc. This component is also making the AC run constantly on low. Call me crazy, but I would say that the whole unit needs replacing. If anyone can give me tips on how to trouble shoot it using a multimeter (I am familuar with how to use a multimeter) I would appreciate it. If you know of a website or location where I might find a replacement unit... that too would be appreciated. I am located in Okinawa japan and my options are a tad bit limited here so any assistance would be GREAT!!!
Thanks for your time, and feel free to share what you know....
Semper Fi