TM 9-6115-670-14&P 4-158 4.62.  START-PREHEAT TOGGLE 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 APU control unit disconnected from shelter. Materials/Parts Momentary Toggle Switch TEST a.  Tag and remove electrical leads from emergency shut-down switch (perform steps a through d of REPLACE). b.  Refer to Figure FO-1 (SICPS/WIN-T) or F0-7 (JTACS). With START-PREHEAT toggle switch (3, Figure 4-50),  in the OFF (center) position, use Multimeter to test for no continuity between center terminal and the upper and lower terminals. If continuity is observed, replace toggle switch. c.  Place and hold START-PREHEAT switch (3) in up position and use Multi-meter to test for continuity across center and upper terminals. If there is no continuity, replace START-PREHEAT switch (3). d.  Place and hold START-PREHEAT switch (3) in down position and use Multi-meter to test for continuity across center and lower terminals. If there is no continuity, replace START-PREHEAT switch (3). REPLACE a.  Remove ten screws (caged nuts (SICPS), machine screws (JTACS and WIN-T)) (1, Figure 4-50) securing APU control unit cover to chassis and remove. b.  At rear of START-PREHEAT switch (3), item (4), identify and tag terminal leads (5). c.  Carefully cut away insulation sleeving (SICPS only) and expose soldered connections. d.  Unsolder and remove terminal leads (5) from terminals. e.  Remove nut (2) securing START-PREHEAT switch (3) to APU control unit cover and remove. f.    Place START-PREHEAT switch (3) through mounting hole and secure START-PREHEAT switch (3) to front panel with nut (2). g.  At rear of START-PREHEAT switch (3, item 4), identify terminal leads (5). h.  Place insulation sleeving (SICPS only) over terminal lead and away from area to be soldered. i.    Solder terminal leads to appropriate switch terminals.  Remove tags from terminal leads.