TM 9-4120-399-14
5-28. COMPRESSOR (B1). (Continued).
a . Test. - Continued.
(4) Check compressor (B1), motor protector, heater (HR7), and thermostat as follows:
(a) Disconnect P3 connector and harness from J3 connector located on compressor
junction box (3).
(b) Remove wing nut (1) from compressor junction box cover (2) and gasket (3)
and pull junction box cover from compressor
(c) Check that all wire connections are secure and in good condition.
(d) Using multimeter, check continuity between connector J3 contacts D to E, D to
F, and E to F. Continuity should be indicated. If continuity is not indicated, check that wires
are properly connected. If wires are properly connected and continuity is still not indicated,
replace compressor.
(e) Check continuity between P3 contacts A and B. If there is no continuity and
wires are properly connected, the motor protector (internal thermostat) is open. Replace the
compressor.
(f) Check continuity between P3 contacts A, B, D, E, and F, and compressor
canister. If wires are properly connected and there is continuity indicated, there is an internal
short. Replace the compressor.
(g) Check continuity between P3 contacts G and H. If there is continuity between
these pins, both the heater element and thermostat are all right. If there is no continuity between
the pins, bare the splice between the heater lead and thermostat lead, and separately check for
If there is continuity
continuity between pin G and the splice, and pin H, and the splice.
between pin G and the splice, but not between pin H and the splice, the heater element is all
right and the thermostat is bad. If there is continuity between pin H and the splice, but not
between pin G and the splice, the thermostat is all right and the heater element is bad. If there
is no continuity between either pin the splice, both the element and the thermostat are bad. If
thermostat is bad, replace compressor. If heater is bad, replace heater.
b. Connector J3 Replacement. (Refrigerant system discharge is not required.)
(1) Removal.
WARNING
Be sure that the power has been disconnected at the power source.
(a) Remove wing nut (1), cover (2), and gasket (3).
( b ) Remove four nuts (4), four lock washers (5), and four screws (6) from
connector J3 (7). Pull the connector out of the box to gain access to the solder connections.
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