BMW K 1100 LT/RS - Manual (Page 109)

12.23
Indicator lamp lights at only half brightness
intensity when engine running.
no
Check contacts of cable connections.
Do cable connections have poor contact. yes
Repair cable connections/plug contacts.
no
Check regulator.
Is regulator defective? yes
Renew regulator.
no
Check carbon brushes.
Are carbon brushes defective? yes
Renew carbon brushes.
no
Check rectifier.
Is rectifier diode defective/does rectifier diode
have short to earth (ground)?
yes
Renew diode carrier.
no
Check alternator.
Does stator have short to earth (ground)? yes
Renew stator.
no
Check rotor.
Does rotor partly have short to earth (ground)? yes
Renew rotor.