TM-9-2320-272-24-1

TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)

TECHNICAL MANUAL; UNIT, DIRECT SUPPORT, AND GENERAL SUPPORT MAINTENANCE MANUAL; VOLUME 1 OF 4

JUNE 1998

  TM-9-2320-272-24-1 - Page 254 of 1015

TM 9-2320-272-24-1
Table 2-3. Electrical Troubleshooting (Contd).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Test. 2. Test circuit breaker.
Step 1.
Disconnect lead 569A to heater switch from circuit breaker.
Step 2.
Set multimeter to 50-volt range, connect negative lead to vehicle chassis ground, and
positive lead to exposed circuit breaker terminal.
Step 3.
Place battery switch to ON position and observe multimeter.
Step 4.
Disconnect lead 569A to battery switch from circuit breaker. Connect multimeter
positive lead to wire and observe multimeter.
a.
If multimeter indicated 12-13 volts in step 3, repair or replace lead 569A between
circuit breaker and heater switch (para. 3-131).
b.
If multimeter indicated 12-13 volts in step 4, replace circuit breaker (para. 3-105).
END OF TESTING!
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