C.E. Niehoff & Co. C701/C701A Troubleshooting Guides - Manual (Page 7)

Page 7
TG3E
Section C: Advanced Troubleshooting
(CONT’D)
Test for battery voltage at alternator B+ terminal. Does battery voltage exist?
Yes No
Repair vehicle wiring as necessary.
Continue test.
Chart 3 – No Alternator Output – Test Charging Circuit
With engine running: Test for battery voltage at
regulator IGN terminal. Does battery voltage exist?
Yes No
Stop engine. Unplug alternator-to-regulator harness. Connect DMM red lead to socket E in harness plug.
Connect black lead to socket A in same plug. Does battery voltage exist?
Yes No
Connect DMM red lead to socket B on alternator-to-regulator harness plug. Connect black lead to socket C
on same plug. Does resistance measure about 1.2 ohms?
STATIC TEST – ENGINE OFF, BATTERY SWITCH ON, KEY ON.
REMOTE-MOUNTED REGULATORS: CHECK CONDITION OF FUSE IN WIRING HARNESS
BEFORE TROUBLESHOOTING
Yes No
Figure 5 – Alternator-to-Regulator Harness Plug
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SOCKET CONNECTIONS
Socket A B–
Socket B Field +
Socket C Field –
Socket D AC
Socket E B+
Repair vehicle wiring as necessary.
Continue test.
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Connect DMM red lead to socket D in harness plug. Connect
black lead to alternator B+ terminal. Does continuity exist?
Yes No
Alternator is defective.
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Yes
Unplug alternator-to-regulator harness. Plug CEN Regulator Bypass Adapter A10-129 into harness plug.
Make sure black lead does not touch ground. Clip red lead to B+ terminal on alternator. (If Adapter is not
available, connect jumper wire from pin B on harness to alternator B+ terminal.) Does spark occur at
alternator B+ terminal?
No
Momentarily (1 sec) touch black lead to ground on alternator
case. [If Adapter is not available, momentarily (1 sec.)
connect jumper wire from pin C on harness to ground.]
Spark will occur at ground. Touch steel tool to shaft to detect
significant magnetism. Is shaft magnetized?
Yes No
Disconnect Adapter or jumper
wire. Alternator is defective.
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Alternator is defective.
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Disconnect Adapter or
jumper wire. Alternator
is defective.
Disconnect Adapter or
jumper wire. Regulator
is defective.
Go to Chart 4, page 8.
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