TM-9-2320-272-23-1

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

TECHNICAL MANUAL; FIELD MAINTENANCE MANUAL; VOLUME 1 OF 5

SEPTEMBER 2012

TM-9-2320-272-23-1 - Page 956 of 1313

FIELD MAINTENANCE

HEATER WILL NOT OPERATE WITH SWITCH IN LOW POSITION (HIGH POSITION OPERATION NORMAL)

INITIAL SETUP:

Tools and Special Tools

Tool Kit, General Mechanic's: Automotive

(Volume 5, WP

0826, Table 1, Item 56)

Multimeter

(Volume 5, WP

0826, Table 1, Item 34)

Test Set, Electronic Systems

(Volume 5, WP

0826, Table 1, Item 51)

Personnel Required

(2)

References

Point to Point Schematics

References (cont.)

Volume 2, WP

0307

Volume 3, WP

0352

Equipment Condition

Vehicle parked and engine shut down.

(TM

9-2320-272-10)

TROUBLESHOOTING PROCEDURE

HEATER WILL NOT OPERATE WITH SWITCH IN LOW POSITION (HIGH POSITION OPERATION NORMAL)

NOTE

Conduct these malfunction tests if heater will not operate with switch in low position. This

procedure will check for faulty heater switch, faulty circuit 569A wire, defective circuit breaker

or battery switch.

TM 9-2320-272-23-1

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