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
SOCKET CONNECTIONS
Socket A B–
Socket B Field +
Socket C Field –
Socket D AC
Socket E B+
Repair vehicle wiring as necessary.
Continue test.
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.
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.
Alternator is defective.
Disconnect Adapter or
jumper wire. Alternator
is defective.
Disconnect Adapter or
jumper wire. Regulator
is defective.
Go to Chart 4, page 8.
R
Section 3: Advanced Troubleshooting (cont.)
Page 7
TG3F
