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Section 4: Advanced Troubleshooting (cont.)
Section 4: Advanced Troubleshooting
Remote-mounted regulator applications: Check condition of fuse in wiring harness
With engine running: Does battery voltage exist at alternator B+ terminal and regulator E terminal?
With key off, engine off: Does battery voltage exist at alternator B+ terminal?
With key off, engine off: Unplug alternator-to-regulator harness. Connect DMM on DC volt scale across
pins A and D, and then across pins C and E in harness plug. Does battery voltage exist for both pairs?
With DMM on resistance scale, does the field resistance between pin F in harness plug and alterna-
torB– terminal measure about 1.6 (±0.2) ohms?
Set DMM to diode test.
Check negative diodes: Connect red lead to pin B in harness plug. Connect black lead to alternator B– termi-
nal. Meter should read OL (over limit). Reverse leads. Meter should read voltage drop.
Check positive diodes: Connect red lead to pin B in harness plug. Connect black lead to alternator B+ termi-
nal. Meter should read voltage drop. Reverse leads. Meter should read OL (over limit).
Momentarily (1 sec.) jumper pin F in harness plug to alterna-
tor B+ terminal. Touch shaft with steel tool to detect significant
magnetism. Is shaft magnetized?
Yes
Regulator is defective.
Page 6
Page 6
(CONT'D)
Chart 1 – No Alternator Output –
before troubleshooting.
Yes
Yes
Yes
Yes
Yes
No
Alternator is defective.
Figure 5 – Alternator-to-Regulator Harness Plug
Quick Diagnostic
Repair vehicle harness circuit to E terminal on regulator
or B+ terminal on alternator.
Repair vehicle harness circuit to B+ terminal on alterna-
tor.
Alternator is defective.
Alternator is defective.
Alternator is defective.
PIN CONNECTIONS
Pin A
GND/B–
Pin B
AC
Pin C
GND/B–
Pin D
B+
Pin E
B+
Pin F
F+
No
No
No
No
No
R
TG0048A
TG48B
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