Check with program tester - see page 11-00/6.
If a program tester is not available:
A) Battery voltage is correct
Connect voltmeter to D + and ground.
At 2000 rpm reading must be 13.5 - 14.6 V.
Regulator is defective when reading is 14.6 V or more.

B) Remove voltage regulator and install a carbon brush holder,
Bosch No. 1 194 336 006.
Connect D + to DF.
Connect test lamp to battery + and jump cable from D + to DF.
1. The alternator is good when lamp is bright with engine off and off
with engine running.
2. The stator winding or diodes are defective if indicator lamp burns.

The voltage regulator can only be replaced together with
the carbon brush holder.
Remove voltage regulator.