BMW Professional means nothing.
There are two types of head units
and three types of sound systems.
1)either you have the Normal Radio or you have idrive/Nav
2)The sound system is stereo = no amp no tweeters
Hi Fi tweeters plus a 6 channel amp in the trunk behind
the US driver side rear wheel well
Top Hi Fi = Logic 7 9 channel amp 13 or 11 speakers tweeters
count as speakers.
Check for water in the amp area first.
Check battery voltage and Alternator Voltage next
Check connections at Radio and Amp. Try re seating them
The head units have a single main connector with a throw switch lock down.
The amp is the same for Hi Fi for logic 7 it is sliding lock connector .
Many ytube video's on these.
BMW stereo types
http://www.e90post.com/forums/showthread.php?t=352586
http://www.e90post.com/forums/attach...2&d=1266451970
http://www.e90post.com/forums/attach...1&d=1209780865
http://bmwcoders.com/forum/3-er-8/bm...1-e92-e93-291/
http://technicpnp.com/menuDiagrams/d...e90_92_93.html
http://www.musicarnw.com/page-2/
http://www.e90post.com/forums/attach...3&d=1169133185
http://www.e90post.com/forums/attach...1&d=1209780605
http://www.e90post.com/forums/showthread.php?t=641323
http://www.e90post.com/forums/attach...4&d=1278871872
http://www.e90post.com/forums/showthread.php?t=343673
https://www.bimmerfest.com/threads/e...n-752.1275694/