Harmony CD/Radio Problem

[stevenicks]

I have a problem with the original factory fitted CD/Radio. Firstly it wont turn off unless I turn the engine off. Secondly it is stuck on the radio function but wwon't allow me to change channels or switch over to the CD function.
Every so often it displays a couple of letters followed by some numbers. It does not ask me for the 4 digit radio code. The CD magazine is fully functional so I can load or eject when required.

Any advice would be appreciated.

Steve