Check the following sites for info on bypassing the TV Control to watch while driving. This sunject has been discussed in another forum and there is a lot of info there.
http://www.mobilecentre.co.uk/index.php?main_page=product_info&cPath=4&products_id=19
http://www.tvonnav.com/home.html
http://www.navtv.com/
http://www.tvfree-modules.com/products-mini-e46-e39-x3-x5-z4.html
Not sure if this works on not
Watch TV / Videotext during driving
This works on all BMW 5/7 Series with the Mark I Navigation System (the one with the male voice).
On Mark II (the newer version with the female voice) you have to use "brightness" instead of
contrast for TV and "color" instead of brightness for videotext to get the trick to work.
This works on the latest 99 7-series models as well. This does not appear to work for the latest BMWs
sold in Europe (2000 onward, 3/5/7 series). The software updates for latest navigation CD-ROM's do not
appear to affect or disable this trick.
set ignition to pos. II
enter TV mode
enter "settings"
enter "contrast"
when the green contrast bar is visible, push the knob and keep it pressed
turn ignition off (keep button pressed!)
wait 8-10 seconds (timing must be accurate!)
release the knob
turn on ignition again
Now the TV will operate while the car is in motion, though you certainly should leave that to your
passengers only while driving. To watch videotext use the same procedure as above, but choose
"brightness" instead of "contrast"
http://www.bimmerfest.com/forums/showthread.php?t=50956