TM 9-2350-256-20 CHAPTER 6: MAINTENANCE OF ELECTRICAL SYSTEMS AND CIRCUITS 6-75 REPLACE/REPAIR BULKHEAD TO AUXILIARY POWER UNIT (APU), MASTER RELAY, AND RIGGER'S LIGHTS WIRING HARNESS (DUAL VOLTAGE) (11672412) THIS TASK COVERS a.  Removal b.  Disassembly c.  Assembly d.  Installation INITIAL SET-UP Tools: Parts: Equipment Condition: Tool kit, general mechanic's   Lockwashers (20) (Appendix Air inlet doors removed (see (Appendix C, item 53) C, item 116) paragraph 9-56)   Lockwashers (4) (Appendix G, item 103)   Lockwashers (4) (Appendix G, item 105) WARNING Be certain MASTER switch is OFF when working on electrical systems to avoid electrical shock and bums. Connector No. Electrical Lead To: Wire No. 1 Bulkhead disconnect 420, 420A, 493, 421, 65, 487, 65, 17, 26 2 Hydraulic pressure switch 61 3 Hydraulic pressure switch 61A 4 APU engine disconnect 421, 65, 487, 65, 66, 62, 478A, 61 5 APU engine disconnect 420, 420A, 493 6 APU wiring harness (11672417) GND 7 Batteries to master relay, voltage regulators, slave receptacle, GND and engine disconnect wiring harness (dual voltage) (11672413) 8 APU voltage regulator 478A, 62, 61 9 Master relay 81 10 Rigger right service light 17 11 Rigger left service light 17 12 Bulkhead to main engine bracket and rear fuel tank transmitter 26 wiring harness (dual voltage) (11672411) 13 Circuit breaker K 14 Bulkhead disconnect 48 15 Bulkhead to main engine wiring harness and starter relay 61 wiring harness 16 Bulkhead to main engine wiring harness and starter relay 61A wiring harness 6-194