TM 9-4520-272-14&P
FIELD (UNIT) MAINTENANCE
LARGE CAPACITY FIELD HEATER
NSN 4520-01-500-1534
MAIN BATTERY POWER SWITCH
TEST, REPLACE
INITIAL SETUP:
Tools
Personnel Required
Tool Kit, General Mechanics (Item 2, WP 0092
MOS 63J or 52C
Materials/Parts
Equipment Condition
Tags, marking, MIL-T-12755 (Item 5, WP 0119
Heater shut down and cool (WP 0005 00)
Disconnect negative battery cable from
outboard battery to cut power to the system
TEST
1. Remove cables from main battery power switch (2) as detailed in steps 1 through 4 below.
2. Set multimeter to read continuity and place leads of multimeter across the front (10) and rear (7)
studs on the main battery power switch (2).
3. Verify that when the main battery power switch (2) is in the ON position, the multimeter reads as a
short circuit (continuity) through the main battery power switch.
4. Verify that when the main battery power switch (2) is in the OFF position, the multimeter should read
as an open circuit through the main battery power switch.
REPLACE
1. Open the engine access door (1) to gain access to the main battery power switch (2) on the rear of
the fuel assembly panel (3).
2. Tag and mark wires connected to main battery power switch (2).
3. Remove rubber insulating boot (4), and then remove nut (5) and wire (6) from the rear stud (7) of the
main battery power switch (2).
4. Remove the nut (8) and wire (9) from the front stud (10) of the main battery power switch (2).
5. Remove the two nuts (11), bolts (12), and lockwashers (13) that secure the main battery power switch
(2) to the fuel assembly panel mounting bracket (14).
6. Remove main battery power switch handle.
7. Remove the defective main battery power switch (2).
0030 00-1
