TM 9-2320-361-34 17-7. ENGINE COOLANT HEATER OVERHEAT SWITCH AND IGNITER REPLACEMENT THIS TASK COVERS: a. Overheat Switch Removal d. Igniter Installation b. Igniter Removal e. Overheat Switch Installation c. Inspection INITIAL SETUP APPLICABLE MODELS MATERIALS/PARTS All Igniter (Appendix F, Item 87) TEST EQUIPMENT REFERENCES (TM) Multimeter (Appendix B, Item 3) TM 9-2320-361-20 TOOLS TM 9-2320-361-34P General mechanic’s tool kit EQUIPMENT CONDITION (Appendix B, Item 1) Engine coolant heater removed (TM 9-2320-361-20). Tool kit, electrical (Appendix B, Item 2) NOTE Tag all leads for installation. I a. Overheat Switch Removal I 1. Remove four screws (6) and guard (7) from heater housing (8). 2. Remove nut-assembled lockwasher (2), ground lead (3), air tube (4), and elbows (1) and (5) from heater housing (8). 3. Disconnect lead (9) from overheat switch (13). 4. Disconnect leads (10) and (12) from tab connector (11) and tab connector (11) from overheat switch (13). 5. Remove nut (33), lockwasher (32), retainer (31), overheat switch (13), washer (14), and O-ring (15) from heater housing (8). b. Igniter Removal 1. Remove four nut-assembled lockwashers (27) and end plate (26) from heater housing (8). 2. Remove screw-assembled lockwasher (21), ground strap (22), igniter lead (23), and lockwasher (24) from burner (16). 3. Remove nut (28), ground strap (22), and lockwasher (29) from stud (30). CAUTION Igniter is fragile. Use care when removing igniter. Failure to do so may result in damage to equipment. 4. Remove nuts (19) and (18), preheater resistor strap (17), igniter (20), and gasket (25) from burner (16). Discard igniter (20). c. Inspection Test overheat switch (13) for continuity. If continuity does not exist, replace overheat switch (13). 17-16