C.E. Niehoff & Co. C803D Troubleshooting Guides - Manual (Page 5)

Page 5 TG32D
Section C: On-Vehicle Troubleshooting
(CONT’D)
No Alternator Output – Test Charging Circuit
• TEST MEASUREMENTS ARE TAKEN ON HARNESS PLUG AT ALTERNATOR. TEST MEASUREMENT AT AN
EXTENDED HARNESS PLUG MAY AFFECT RESULTS.
• REMOTE-MOUNTED REGULATORS: CHECK CONDITION OF FUSES IN WIRING HARNESS BEFORE TROUBLE-
SHOOTING.
• BEFORE STARTING DIAGNOSTIC SEQUENCE, VERIFY THE FOLLOWING AND REPAIR/REPLACE IF NOT
TO SPEC:
—BATTERIES FOR STATE-OF-CHARGE (24.5-25.5 V), CONDITION, AND SECURE CONNECTIONS
—MASTER BATTERY SWITCH FOR FUNCTION
If you have questions about your alternator or any of these instructions, 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]
MASTER BATTERY SWITCH ON, KEY ON, ENGINE ON: Test for battery voltage at B+ terminal on alternator to
ground, then at IGN terminal on regulator to ground (A2-363: unplug 3-pin harness plug and test pin C [Eng] at
plug to ground; A2-341 regulator: See page 2 for more information). Does battery voltage exist at both locations?
Yes No
Figure 8 – CEN 6-pin A10-114 Inline Harness Tool
Socket Connections
SOCKET CONNECTIONS
Socket A Not used
Socket B Not used
Socket C B –
Socket D B+
Socket E Phase
Socket F F+
MASTER BATTERY SWITCH ON, KEY ON, ENGINE OFF: Readings of all four tests must pass.
1. Battery voltage test: Connect DMM red lead to socket D in test tool. Connect DMM black lead to socket C in test
tool. Battery voltage should exist.
2. Field coil resistance test: Set DMM on Ohms test. Field resistance between sockets F and C in test tool should
measure nominal 1.0-1.5 ± 0.2 ohms. Field coil is defective if reading is less than 0.5 ohms or greater than 3 ohms.
3. Significant magnetism test:
a. Securely connect one end of a jumper wire to socket F in test tool.
b. Momentarily (1 sec.) touch other end of jumper wire to alternator B+ terminal. Spark will occur at B+ terminal.
Touch steel tool to shaft to detect significant magnetism.
4. Phase supply test: Set DMM to diode test. Connect DMM black lead to socket E in test tool. Connect red lead to
alternator B+ terminal. DMM should read blocking in this direction. Then reverse leads. DMM should read flow
in this direction. Repeat for socket E and B– terminal. Tests should read flow in one direction and blocking in
the other direction.
Yes No
Alternator is defective.
Disconnect 6-pin alternator-to-regulator harness
plug at regulator and connect CEN A10-114 inline
test tool to harness plug end only. Make sure
connections are secure.
Regulator is defective.
Repair vehicle wiring as necessary. Run engine and
re-test charging circuit. Is charging system perform-
ing properly?
System is operative.
No Yes
A B C D E F
Figure 9 – A2-363 3-pin Harness
Pin Connections
PIN CONNECTIONS
Pin A D+
Pin B Phase out
Pin C Eng