TM 5-3825-225-14&P
(3)
Reset the tattletale switch and turn ignition switch to ON. If the tattletale switch does not actuate
when the temperature probe is placed in the water, replace the temperature gage switch after
checking the tattletale switch.
c.
Testing Oil Pressure Gage. The oil pressure gage switch can be tested without removing it from the engine
instrument control panel.
(1)
Disconnect the pressure line from the oil pressure gage.
(2)
Apply a known pressure to the oil pressure gage switch and compare the gage reading with the
actual pressure. If the oil pressure gage reading is inaccurate, replace the oil pressure gage switch.
(3)
Reset the tattletale switch and turn the ignition switch to ON.
(a)
Apply a pressure less than 25 psi (172 kPa) to the oil pressure gage switch.
(b)
Apply a pressure greater than 60 psi (414 kPa) to the oil pressure gage switch. If the tattletale
switch fails to actuate in both cases above, replace the pressure gage switch after checking the
tattletale switch.
d.
Testing Ammeter. Check the accuracy of the ammeter with an ampere meter. If the ammeter is faulty,
replace it.
e.
Installation (See Figures 4-5 and 4-6).
(1)
Install temperature gage (4, Appendix F, Figure 2) to control panel with mounting bracket and nuts.
(2)
Connect lead wires to temperature gage (4).
(3)
Attach temperature probe to engine block.
(4)
Install oil pressure gage (5) to control panel with mounting bracket and nuts.
(5)
Connect wire leads to oil pressure gage(5).
(6)
Connect pressure line to engine and oil pressure gage (5).
(7)
Install ammeter (6) to control panel with mounting bracket and nuts.
(8)
Connect wire leads to ammeter (6).
(9)
Attach tachometer sending unit to engine block (see Figure 4-6).
(10)
Install tachometer (1, Appendix F, Figure 2) in control panel with mounting bracket and nuts.
(11)
Connect lead wires and sending unit wires to the tachometer (1).
4-16.
MAIN JUNCTION BOX MAINTENANCE.
a. Removal and Disassembly (See Appendix F, Figure 3).
b.
NOTE
Identify and tag all wires as they are disconnected. This will aid in reassembly.
(1)
Disconnect power lines from junction box receptacles (3 and 5).
(2)
Remove screws (7) and enclosure (6) from junction box.
(3)
Disconnect wires from terminal block (13), fuse block (10), resistors (21 and 29), and receptacles (3
and 5).
(4)
Disconnect conduit (5, Appendix F, Figure 10) from junction box.
(5)
Remove screws (33, Appendix F, Figure 3), nuts (32), and lockwashers (31) from junction box and
separate junction box from mounting bracket. Discard lockwashers.
(6)
Remove nuts (8) and lockwashers (9) from enclosure (6) and separate it from junction box. Discard
lockwashers.
(7)
Remove circuit breakers (12) from fuse block (10).
(8)
Remove screws (11) and fuse block (10) from enclosure (6).
(9)
Remove screws (11) and terminal block (13).
(10)
Remove screw (28), nut (23), lockwasher (24), washers (26 and 27), and resistor (29). Discard
lockwasher.
4-16
