ARMY TM 9-4120-380-14
AIR FORCE TO 35E9-136-21
AIRFLOW FILTER SWITCH (S3) This task covers inspection, testing, removal and installation.
Tool kit, service, refrigeration unit (Item 1, Appendix B)
Disconnect input power to the air conditioner before performing any internal
maintenance Voltages used can KILL. Shutting the unit off at the control panel does not
disconnect unit power.
(1) Disconnect air conditioner input power at source; and
The following steps may require two persons.
Remove cover screw (2) and unsnap cover (1) from switch (3) (see fig. 4-45).
Tag and disconnect leads
Remove air hose (7).
Remove two nuts (6), lockwashers (5), and flat washers (4)
Remove switch (3)
a. Check for airflow through switch (3). If airflow is restricted, replace switch
b. Check switch (3) for cracks, breaks or dents. Replace If damaged
a. Connect multimeter probes between the common and open electrical terminals. Check continuity between
electrical terminals. Switch contacts should be open.
b. Turn adjustment screw back and forth slightly and check that switch contacts open and close on narrow band
c. Reset switch so contacts are open. If switch fails above tests, replace switch.