Page 5
TG3E
Section C: Advanced Troubleshooting
(CONT’D)
Figure 3 – Alternator-to-Regulator Harness Plug
Chart 1 –
No Alternator Output –
Quick Diagnostic
With engine running, does battery voltage exist at alternator B+ terminal and regulator IGN terminal?
Yes
No
Repair vehicle harness circuit to IGN terminal on regulator
or B+ terminal on alternator.
With key off, engine off: Unplug alternator-to-regulator harness. Connect DMM on DC volt
scale across sockets A and E in harness plug. Does battery voltage exist?
Yes
No
Alternator is defective.
With DMM on resistance scale, ensure that the field resistance measured between sockets B and C in
harness plug is about 1.2 (±0.2) ohms.
Yes
No
Alternator is defective.
Install a jumper from socket B in harness plug to B+ terminal on alternator. Momentarily (1 sec.) jumper
socket C in harness plug to alternator B– terminal. Touch shaft with steel tool to detect significant mag-
netism. Is shaft magnetized?
Yes
No
Go to Chart 3, page 7.
Regulator is defective.
SOCKET CONNECTIONS
Socket A B–
Socket B Field +
Socket C Field –
Socket D AC
Socket E B+
R
Section 3: Advanced Troubleshooting (cont.)
Page 5
TG3F
