TG0007A
C. E. Niehoff & Co.
BRUSHLESS ALTERNATORS
Test for battery voltage at B+ terminal on alternator to ground, then at F+ terminal on regula-
tor to ground. Does battery voltage exist?
Yes
No
Repair vehicle wiring as necessary. Continue test.
Vehicle charging circuit test is complete.
Remove jumper wire. Run engine and
re-test charging circuit for operation.
Chart 2 – No Alternator Output –
Ener
Ener
Ener
Ener
Energize Switch
gize Switch
gize Switch
gize Switch
gize Switch
– Test Charging Circuit
Jumper B+ terminal on alternator to E terminal
on regulator. Touch shaft with steel tool to detect
significant magnetism. Is shaft magnetized?
Yes
No
Go to energize switch on engine in E circuit.
Test for battery voltage going into energize switch
from battery. Does battery voltage exist?
Yes
No
Make sure jumper wire from alternator B+
terminal to regulator E terminal is still attached.
Test for battery voltage at energize switch E
terminal connection. Does battery voltage exist
at energize switch?
E circuit from regulator
to energize switch is
good. Energize switch is
defective.
Repair vehicle circuit to
energize switch. Continue test.
Yes
No
Repair vehicle circuit
from E teminal on
regulator to energize
switch on engine.
Yes
Unplug alternator-to-regulator harness. Plug CEN
Regulator Bypass Adapter A10-129 into harness
plug. Make sure black lead does not touch
ground. Clip red lead to B+ terminal on alternator.
(If Adapter is not available, connect jumper wire
from socket B on harness to alternator B+ termi-
nal.) Does spark occur at alternator B+ terminal?
Disconnect Regulator Bypass Adapter or jumper
wire. Connect DMM red lead to socket E in alter-
nator-to-regulator plug. Connect black lead to
socket A in same plug. Does battery voltage exist?
Regulator is defective.
Yes
No
Disconnect Adapter or jumper
wire. Alternator is defective.
No
Alternator is defective.
Touch black lead to ground on alternator case.
(If Adapter is not available, connect jumper wire
from socket C on harness to ground.) Spark will
occur at ground. Touch steel tool to shaft to
detect significant magnetism. Is shaft magne-
tized?
Yes
No
Disconnect Adapter or jumper
wire. Alternator is defective.
R
Section 3: Advanced Troubleshooting (cont.)
Page 5
TG7B
