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TM5-4120-387-14
4-38. HEATER RELAY (K2)
Preliminary procedure:
Remove junction box.
(See para 4-29.)
a.
Access
(1) Using screwdriver,
loosen four captive panel fastener screws in
junction box cover.
(2) Remove junction box cover.
(3) with wrench,
remove the four nuts and lockwashers that secure the
terminal guards.
(4) Tag and disconnect wire leads.
b.
Inspection
(1) Check for loose, corroded,
missing, or broken terminal connect
(2) Check relay for cracks, evidence of overheating, and other vis
damage.
Replace if damaged.
c.
Test
ions.
ible
(1) Use continuity tester or a multimeter set on the lowest OHMS scale to
check continuity between terminals A1 and A2, B1 and B2, and C1 and C2. All three
contacts should be open.
If there is continuity, replace the relay.
(2) Check continuity between coil terminals X1 and X2. If there is no
continuity, the coil is open. Replace the relay.
(3) Apply external 24 volts dc power across terminals Xl and X2 and repeat
continuity checks between terminals A1 and A2, B1 and B2, and C1 and C2.
All
three contacts should be closed.
If there is no continuity, replace the relay.
(4) Remove the external 24 volts dc power source from coil terminals Xl and
X2.
d.
Removal
(1) Remove junction box. (See para 4-29.)
4-91
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