BMW K 1100 LT/RS Repair Manual page 110

Indicator lamp lights at half or full brightness
with engine running.
no
Check regulator.
Is regulator defective?
no
Check supply line.
Does supply line have break/short circuit?
no
Check carbon brushes.
Are carbon brushes defective?
no
Check rotor winding.
Is rotor winding defective?
no
Check exiter current circuit.
Is exiter current circuit broken?
no
Check diode/diode carrier.
Is diode/diode carrier defective?
no
Check cable D +/61.
Has cable short to ground?
12.24
yes
Renew regulator.
yes
Repair break;
renew cable/connection elements.
yes
Renew carbon brushes.
yes
Replace rotor.
yes
Repair break;
renew cable/connection elements.
yes
Replace diode/diode carrier.
yes
Repair short-circuit;
if necessary renew cable.