We have a 2004 facelift ZT-T 260 SE wth std factory sat nav / stereo unit (BMW)

can anyone advise of help or what fault might be.

SAT NAV part works fine so its not dvd unit in boot, screen is fine, map etc but no sound for route instructions

right hand power button for stereo doe not light up so no radio / cd / cassette function, no sound and the stereo buttons dont work. is there a seperate fuse for the stereo part of the unit

the car obviously has the power unit in the boot floor plus it has Harnon kardon system

we are tryig to work out if it is the unit at fault or whether it could be the external amp to make it work ?

anyone had a similar fault, any thoughts or advice welcome

regards

James