C.E. Niehoff & Co. N1380-2 Troubleshooting Guides User Manual
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TG0037A
Section C: Advanced Troubleshooting
If you have questions about your alternator or any of these test procedures, or if you need to locate a Factory Authorized Service Distributor, 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]
Ignition switch on, engine off: Check for battery voltage between B–
terminal on alternator and Pin A on output receptacle (back-probe pin).
Ignition switch off: Back-probing pins, momentarily (1 sec.) jumper
Pins A and B in the output receptacle. Touch shaft with steel tool
to detect any magnetism. Is shaft magnetized?
Yes
No
Yes
No
Repair vehicle wiring to
output receptacle.
Figure 3 – Regulator 5-pin Receptacle
Chart 1 – No Output
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Check ignition switch
and vehicle wiring.
Disconnect regulator harness and output harness. Perform series
of tests with DMM:
1) With meter set on diode test, connect red lead to pin C of output
receptacle and black lead to pin D of regulator receptacle. Meter
should read continuity. Reverse leads. Meter should read OL.
2) With meter set on ohms, check field coil resistance across
pins A and D of regulator receptacle. Resistance should measure
less than 3 ohms.
3) With meter set on ohms, check for continuity between pin C of
regulator receptacle and B– terminal on alternator.
Did all three tests provide correct readings?
Yes
No
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Regulator is defective.
Alternator is defective.
PIN CONNECTIONS
Pin A
Field –
Pin B
Energize
Pin C
Ground
Pin D
B+
Pin E
Not Used
Figure 4 – Output 3-pin Receptacle
PIN CONNECTIONS
Pin A
B+
Pin B
Energize
Pin C
Phase