TM 9-4110-258-13
4. 23 THERMOSTAT S3 OR SWITCH (HEATER LOCKOUT) S9 TESTING AND REPLACEMENT. Continued
(10) Using multimeter set to measure continuity, check switch (4) continuity between terminals C and NO with
switch button out and pushed in. Continuity should be indicated only when the switch is pushed in. If
continuity was indicated when the button was out or no continuity was indicated when the button was
pushed in, replace switch.
(11) Using multimeter set to measure continuity, check switch (4) continuity between terminals C and NO with
thermostat setting at 12 F (-11 C) and at 28 F (-2 C). Continuity should be indicated only when the
setting is at 28F (-2C). If continuity was indicated at 12F (-11C) setting, adjust thermostat cam per
installation instructions below.
(12) If no failure was indicated, slip clamp (8) over sensing bulb (9).
(13) Install clamps (8) and (10), flat washer (7), new lock washer (6), and screw (5).
(14) Carefully push circuit breaker cover (2) into place and install six screws (1).
b.
Removal
(1) Be sure power has been disconnected at the source and remove six screws (1).
(2) Carefully pull circuit breaker cover (2) out to expose thermostat (3) and switch (4) terminals.
(3) Check gasket (11) material for damage. If damaged, notify direct support maintenance to replace it.
(4) Tag wire leads (12) then remove screws (13) and wire leads.
(5) Tag and disconnect wire leads (14).
(6) Remove screw (5), lock washer (6), and flat washer (7). Discard lock washer
(7) Remove clamp (8).
(8) Remove tie down straps (15).
(9) Loosen setscrew (16) and remove knob (17).
(10) Remove two self locking nuts (18) and bolts (19). Discard self locking nuts.
(11) Remove remote bulb thermostat (3) and any grommets (20) necessary to remove sensing bulb (9).
(12) Remove any silicone RTV remaining in evaporator frame grommet (20).
(13) Loosen setscrew (21) and remove cam (22).
(14) Squeeze tabs on side of switch (4) and remove.
(15) If thermostat bracket (23) is damaged, remove two screws (24) and bracket.
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