Here some links, if you use the search with IHKA there is much more on this subject

click 1

click 2
Under related links on teh rights ide 'E38.org/e32/ there is also a complete write-up for technicians about the IHKA function for technicians for troubleshooting but it is in German language (about 50 pages) , even if you do not understand German the drawings will help.
If the light is on in the dash then it is undercharging=alternator/voltage regulator defective. The voltage regulator always charges. The light is above the check control where you see the battery pic.
"buddy said bosch won't charge unless light on dash comes on when key is in run mode": tell buddy he is wrong.
Use a multimeter and test the battery first and then the charging voltage in idle and at about 1.500 RPM.
You can also unlock the board computer to see the voltage charging under test # 9.
Use search for OBC unlocking.
Let us know what you read. Best is to read at the plus pole under the hood and good ground connection, the BC indicates usually a little bit less due to the length of the wires/connections etc = losses.

shogun >>E32 750iL<< 11/88
7 series Tech tips
http://tinyurl.com/3486c

• 2 q's a/c and charging - dr750 2006-06-23 22:51:41 (98 views)
  • 2 q's a/c and charging (url) - shogun 2006-06-23 23:49:34 (119 views)
    • Direct to German IHKA manual (url) - leersmd 2006-06-23 23:58:52 (412 views)
      • thx guys - dr750 2006-06-24 10:12:31 (74 views)