C.E. Niehoff & Co. C629 Troubleshooting Guides User Manual

Page 4

Page 4

TG72A

Section B: On-Vehicle 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]

No Alternator Output – Test Charging Circuit

• 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

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.

Yes

Figure 5 – CEN 6-pin A10-114 Inline Harness Tool

Socket Connections

SOCKET CONNECTIONS

Socket A Not used

Socket B Phase

Socket C B –

Socket D B+

Socket E D+

Socket F F+

MASTER BATTERY SWITCH ON, KEY OFF, ENGINE OFF: Readings of all five 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 to ohms test. Field resistance between socket F and C in test tool should mea-

sure 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. Turn off master battery switch. Disconnect B+ battery cable on alternator. Set DMM to diode test. Connect black

lead on DMM to socket E in test tool and red lead to B+ terminal on alternator. DMM should read OL. Reverse

leads. DMM should read OL again. Reconnect B+ battery cable to alternator. Turn on master battery switch.

5. Phase taps test: Set DMM to diode test. Connect DMM black lead to socket B 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 B and B– terminal. Tests should read flow in one direction and blocking in

the other direction.

Yes

Alternator is defective.

ENGINE OFF: 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

performing properly?

System is operative.

Yes

A B C D E F