C.E. Niehoff & Co. C627/C628/C631/C656/C657/C658/C671/C680 Troubleshooting Guides - Manual (Page 7)

Page 7
TG30G
Regulator is defective.
Set DMM to diode test. Connect black lead of DMM to B+ terminal on alternator. Con-
nect red lead to pin B on harness plug. DMM should read voltage drop. Reverse leads.
DMM should read OL.
Check continuity of thermal switch inside con-
trol unit: Remove drive end cover on alternator.
With DMM, check continuity between pin B on
harness plug and diode shown in Figure 9
below. Does continuity exist?
Yes No
Yes No
Alternator is
defective.
Chart 3 – Continuation of Chart 1 and 2 as Noted



Thermal switch
in control unit
is defective.

Figure 9 – Diode Arrangement Inside Drive End Housing
USE THIS DIODE

Section C: Comprehensive 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: [email protected]
Visit our Web site: www.CENiehoff.com