A little early morning research in the 3200 operation manual: Timer indicator light
" Press to activate the Timer and cut in the loudspeakers connected to BeoSound 3200
The green indicator light will show when the Timer function is activated
If you do not wish to store your Timer, pressing when STORE ? is displayed, changes the display to EXIT ?. Press GO to exit the Timer function without storing the Timer.
If you leave the Timer function by pressing for example a source button, before the Timer has been stored, the Timer is automatically cancelled. "
Now you should be able to turn the light off by cancelling it. I didn't bring the manual with me on Holiday. I just went online and found at it in the BEOWORLD MANUALS LIBRARY.
Another good reason for Gold membership here.