C.E. Niehoff & Co. C612/C617/C621/C624 Troubleshooting Guides - Manual (Page 5)

Page 5 TG2D
If you have questions about your alternator or any of these test procedures, or if you need to locate a Factory Authorized Service Dealer, please contact us at:
C. E. Niehoff & Co.• 2021 Lee Street • Evanston, IL 60202 USA
TEL: 800.643.4633 USA and Canada • TEL: 847.866.6030 outside USA and Canada • FAX: 847.492.1242
E-mail us at [email protected]
Section C: Advanced Troubleshooting
Self-energized alternator may have lost magnetism. Touch steel tool
to shaft to detect any magnetism. Is shaft magnetized?
Momentarily (1 sec.) jumper D+ terminal on regula-
tor to B+ terminal on alternator. Touch shaft with
steel tool to detect significant magnetism. Is shaft
magnetized?
Yes No
Yes No
Figure 6 – Alternator-to-Regulator Harness Plug
Chart 1 – No Output
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
Install a jumper from B+ terminal on alternator to
socket B in harness plug. Momentarily (1 sec.)
jumper socket C to B– terminal on alternator. Touch
shaft with steel tool to detect significant magnetism.
Is shaft magnetized?
Yes No
Set DMM to diode test. Connect black lead of DMM
to socket B in harness plug. Connect red lead to B+
terminal on alternator. DMM should read OL.
Reverse leads. DMM should also read OL.
Unplug alternator-to-regulator harness. Connect
DMM across socket A and socket E in harness plug.
Does battery voltage exist?
Yes No
Alternator is defective.


Yes No

Alternator is defective.



Alternator is defective.

Yes No

Alternator is defective.

Regulator is defective.
Remove jumper from D+ to B+.
 
SOCKET CONNECTIONS
A B–
B Field +
C Field –
D AC
E B+

Set DMM to Diode Test. Connect DMM red lead to
socket D on alternator-to-regulator harness plug.
Connect black lead to alternator B+ terminal.
Does continuity exist?