TM-9-2320-280-20-1
TRUCK, UTILITY: M998 SERIES
TECHNICAL MANUAL; UNIT MAINTENANCE; VOLUME 1 OF 3
JANUARY 1996
TM-9-2320-280-20-1 - Page 307 of 888
2-222
Change 2
TM 9-2320-280-20-1
ALTERNATOR
DIAGNOSTIC FLOWCHART
F1
GO TO F4,
Page 2-224
TEST OPTIONS
Visual
REASON FOR QUESTION
Must know model of
alternator to perform proper
tests.
TEST OPTIONS
STE/ICE Test 10 and 89,
(pages 2-734 and 2-750).
REASON FOR QUESTION
Determine if high or low
output voltage.
TEST OPTIONS
STE/ICE Test 89,
(page 2-750).
REASON FOR QUESTION
Wire 568A and wire 568
carry ignition current to turn
on regulator.
F3
F2
NO
YES
SEE NOTE ON
OPPOSITE
PAGE.
IS THIS A NIEHOFF 100 AMP
SINGLE VOLTAGE ALTERNATOR?
START ENGINE AND ALLOW TO
IDLE AT 1200-1500 RPM.
RECHECK VOLTAGE OUTPUT.
IS ALTERNATOR OUTPUT LESS
THAN 26 VOLTS?
STOP ENGINE. DISCONNECT WIRE
568A FROM ALTERNATOR WIRE
568. TURN ROTARY SWITCH TO
“RUN”. MEASURE VOLTAGE AT
THE WIRE THAT IS NOT
CONNECTED TO THE
ALTERNATOR. IS THERE BATTERY
VOLTAGE?
NO
YES
IF OUTPUT VOLTAGE
IS OVER 30.5 VOLTS,
REPLACE REGULATOR
(Para. 12-22).
NO
YES
NOTIFY DS MAINTENANCE
TO REPAIR OR REPLACE
WIRE HARNESS.
F
FROM B1,
Page 2-205
KNOWN INFO
VOLTAGE OUTPUT
INCORRECT
POSSIBLE PROBLEMS
WIRING
ALTERNATOR
REGULATOR
KNOWN INFO
VOLTAGE OUTPUT
INCORRECT
POSSIBLE PROBLEMS
WIRING
ALTERNATOR
REGULATOR
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