TM 9-4120-404-14
(c) Check that wire connections in junctio n box area are in good condition.
(d) Using multimeter, check continuity between connector J4 contacts D to E, D to F, and F. to F.
Multimeter should indicate identical ohms resistance. If proper resistance is not indicated, check that wires are properly
connected. If wires are properly connected and proper resistance is still not indicated, compressor motor is defective and
compressor must be replaced.
(e) Check continuity between J4 contacts A and B. If there is no continuity and wires are properly
connected, the compressor motor thermal cutout switch is defective. Replace thermal cutout switch.
(f) Scratch paint on compressor casing and set multimeter to highest ohm setting. Check continuity
between J4 contacts A, B, D, E, and F, and compressor casing. If wires are properly connected and there is any reading
other than infinity indicated, there is an internal ground. Replace compressor.
(g) Check continuity between J4 contacts G and H. If there is continuity between these pins, the
is defective and must be replaced.
(h) If compressor hums and then cycles off on overload, check current draw of compressor motor.
Check current draw on each power lead connected to compressor. If amperage draw is 45 or greater, compressor rotor is
locked and compressor must be replaced.
(1) Connector J4 Replacement. (Refrigerant system discharge is not required.)
(a) Removal.
WARNING
Be sure that the power has been disconnected at the power source.
1. Remove two screws (2) and two lock washers (3).
2. Remove four nuts (4), four lock washers (5), and four screws (6) from connector J4 (7). Pull the
connector out of the box to gain access to the solder connections.
3. Tag and unsolder wires from connector J4 (7).
(b) Installation.
1. Using wire tags installed during removal and wiring diagram Figure 1-5, solder wires to new J4
connector (7). Remove the tags.
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