ARMY TM 9-6115-670-14&P 4-38 4.17.  LOW OIL PRESSURE SWITCH. This task covers:    a.  Test b.  Replace INITIAL SETUP Tools General Mechanic's Tool Kit (Item 1, Appendix B) Shop Equipment, Electrical Repair, Semitrailer Mounted (Item 3, Appendix B) Equipment Conditions MASTER ON-OFF switch on APU control unit set to OFF. Materials/Parts Low Oil Pressure Switch Sealing Compound (Item 17, Appendix F) TEST a.  Remove one screw and lock washer (3, Figure 4-4 (sheet 1)) securing lead (2) to low oil pressure switch (1).  Retain hardware. b.  Tag and remove lead (2) from low oil pressure switch (1). c.  Connect one multimeter lead to low oil pressure switch (1) post, and connect the other multimeter lead to ground.  If continuity is observed, proceed to step d.  If not, replace low oil pressure switch. d.  Install lead (2) on low oil pressure switch (1). e.  Secure lead with one lock washer and screw (3). f.   On APU control unit, position MASTER ON-OFF switch to ON.  Low oil pressure fault indicator on control unit should light. g.  Start APU (para 2.5.).  After a few seconds, fault indicator should go out as engine oil pressure builds past 7 psig (48.26 kPa).   h.  If low oil pressure fault indicator on APU control unit remains lit, shut down the APU (para 2.6) and replace low oil pressure switch. REPLACE a.  Remove one screw and lock washer (3, Figure 4-4 (sheet 2)).  Retain hardware. b.  Tag and remove lead (2) from low oil pressure switch (1). c.  Remove low oil pressure switch (1) from engine. NOTE When   removing   low   oil   pressure   switch,   have   suitable   container available to receive oil spillage.  Collect oil in an appropriate chemical resistant container for disposition/disposal through the local servicing Defense Reutilization and Marketing Office.