C.E. Niehoff & Co. C722 & C724 Troubleshooting Guides - Manual (Page 6)

Page 6 TG71A
Section C: Advanced Troubleshooting
(CONT’D)
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]
Set DMM to diode test. Connect black lead of DMM to B+ terminal on alternator.
Connect red lead to pin B on harness plug. DMM should read voltage drop. Reverse
leads. DMM should read OL.
Chart 3 – Continuation of Chart 2 as Noted
Figure 5 – Diode Arrangement inside Drive End Housing
USE THIS DIODE

Repair vehicle circuit to E or IGN
terminal. Vehicle charging circuit test
is complete. Check continuity of thermal switch inside control
unit: Remove drive end cover on alternator. With
DMM, check continuity between pin B on harness
plug and diode shown in Figure 5 below. Does con-
tinuity exist?
Yes No
Yes No
Alternator is
defective.



Thermal switch
in control unit
is defective.
