Replacement of the APU Electrical Harness (131-9(A))

TASK 49-15-11-960-801-A
Replacement of the APU Electrical Harness (131-9(A))

WARNING: DO NOT TOUCH THE APU UNTIL IT IS SUFFICIENTLY COOL TO PREVENT BURNS WHEN YOU DO THE MAINTENANCE TASK(S).

WARNING: DISCONNECT THE LOW-TENSION ELECTRICAL SUPPLY 6 MINUTES BEFORE YOU START WORK ON THE IGNITION SYSTEM. THE HIGH CURRENT AND VOLTAGE WHICH ARE USED IN THE IGNITION SYSTEM CAN KILL YOU.

WARNING: LOCK THE MECHANISM OF THE ACCESS DOOR 316AR WITH THE PIP PIN WHEN YOU OPEN THE ACCESS DOOR. THIS WILL PREVENT INJURY.

WARNING: MAKE SURE THAT THE SAFETY DEVICES AND THE WARNING NOTICES ARE IN POSITION BEFORE YOU START A TASK ON OR NEAR:

THE FLIGHT CONTROLS
THE FLIGHT CONTROL SURFACES
THE LANDING GEAR AND RELATED DOORS
COMPONENTS THAT MOVE.

MOVEMENT OF COMPONENTS CAN KILL OR CAUSE INJURY TO PERSONS AND/OR DAMAGE TO EQUIPMENT.

WARNING: BEFORE YOU START WORK, YOU MUST PUT ON A SAFETY HARNESS AND ATTACH IT TO THE ACCESS PLATFORM. WITHOUT A SAFETY HARNESS, YOU CAN FALL. THIS CAN KILL YOU OR CAUSE YOU INJURY.

CAUTION: USE THE CORRECT ASSEMBLY PROCEDURE AND TOOLS FOR THE HARNESS CONNECTOR INSTALLATION. IF YOU DO NOT, A DAMAGED OR LOOSE CONNECTOR CAN OCCUR. A LOOSE CONNECTOR CAN CAUSE UNSATISFACTORY ENGINE OPERATION, DECREASED LIGHTNING PROTECTION, AND A POSSIBLE IN-FLIGHT SHUTDOWN.

CAUTION: MAKE SURE THAT THERE IS A SUFFICIENT DISTANCE BETWEEN THE ELECTRICAL HARNESSES AND THE STRUCTURE. IF THE DISTANCE IS NOT SUFFICIENT, THERE IS A RISK OF CHAFING OF ELECTRICAL HARNESSES WITH THE STRUCTURE. CHAFING CAUSED BY OPERATIONAL VIBRATIONS CAN CAUSE MUCH DAMAGE ON ELECTRICAL HARNESSES AND WIRING.

CAUTION: DO NOT TWIST OR BEND THE ELECTRICAL HARNESS WHEN YOU DISCONNECT/CONNECT THE ELECTRICAL CONNECTOR. IF YOU DO, YOU CAN CAUSE DAMAGE TO THE HARNESS AND THUS CAUSE ELECTRICAL CIRCUIT DEFECTS.

ZONE: 315
ZONE: 316

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 4M (13 FT)-ADJUSTABLE
No specific	AR	CAP - BLANKING
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
315	TAIL CONE APU AND ACCESSORY COMPARTMENT
316	TAIL CONE APU AND ACCESSORY COMPARTMENT
315AL, 316AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 24-42-00-861-001-A	Energize the Ground Service Network from the External Power
TASK 24-42-00-862-001-A	De-energize the Ground Service Network Supplied from the External Power
TASK 29-00-00-864-001-A	Put the Related Hydraulic System in the Depressurized Configuration before Maintenance Action
TASK 49-00-00-710-009-A	Self-Test of the ECB
TASK 49-00-00-710-010-A	Operational Test of the APU
TASK 52-41-00-010-001-A	Open the APU Doors for Access
TASK 52-41-00-410-001-A	Close the APU Doors after Access
Replacement of the APU Electrical Harness (131-9(A))

3. Job Set-up
Subtask 49-15-11-860-050-A ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration
(1) Energize the ground service network
(Ref. AMM TASK 24-42-00-861-001).
(2) On panel 25VU, make sure that the APU MASTER SW is in the OFF position.
(3) Put a WARNING NOTICE(S) in the cockpit to tell persons not to start the APU.
(4) Make sure that the hydraulic systems are depressurized
(Ref. AMM TASK 29-00-00-864-001).

Subtask 49-15-11-865-050-A ** ON A/C NOT FOR ALL

B. Open, safety and tag this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	APU/APU/CTL	2KD	L42
121VU	APU/ECB/SPLY	1KD	L41

Subtask 49-15-11-010-050-A ** ON A/C NOT FOR ALL

C. Get Access
(1) Put an ACCESS PLATFORM 4M (13 FT)-ADJUSTABLE below APU access doors 315AL and 316AR.
(2) Open APU access doors 315AL and 316AR (Ref. AMM TASK 52-41-00-010-001).
(3) Set the LIGHT control SW 11LJ to the ON position.

4. Procedure
Subtask 49-15-11-020-050-A ** ON A/C NOT FOR ALL

A. Removal of the APU Electrical Harness
(1) Record the wiring routing and the clamp positions for the installation procedure.
(2) Before you disconnect the electrical connectors, make sure that there is identification on them. This is important for the subsequent installation procedure.
(3) Disconnect connectors P1, P2 and P3.
(4) Put the CAP-BLANKING on each disconnected electrical connector and receptacle.
(a) To prevent contamination, put blanking caps on all the disconnected electrical connectors each time you disconnect a connector.
(5) Disconnect connector P4 from the generator.
(6) Disconnect the starter terminals (4), (5) and (6) from the starter motor:
(a) Remove the terminal protector (9) from the starter motor.
(b) Remove the nuts (2) and (8) and the washers (3) and (7) from the terminal studs.
(c) Remove the starter terminals (4), (5) and (6) from the terminal studs.
(d) Install the washers (3) and (7), nuts (2) and (8) and terminal protector (9).
(7) Disconnect connector P19 from the Fuel Control Unit (FCU).
(8) Disconnect connector P17 from the low fuel-pressure switch.
(9) Disconnect connector P15 from the de-oil solenoid.
(10) Disconnect connector P11 from the oil temperature sensor.
(11) Disconnect connector P9 from the oil pump.
(12) Disconnect connector P5 from the oil pump.
(13) Disconnect connector P21 from the Inlet Guide Vane (IGV) actuator.
(14) Disconnect connector P26 from the speed sensor.
(15) Disconnect connector P28 from the oil heater or from the dummy cover-plate connector, if installed.
(16) Disconnect connector P12 from the load control valve.
(17) Remove the APU electrical harness (1) from the spring clips at all the rubber grommet locations between connector P19 and the clamp (21).
(18) Disconnect connector P13 from the flow divider solenoid.
(19) Disconnect connector P10 from the ignition unit.
(20) Disconnect connector P6 from the inlet temperature sensor.
(21) Disconnect connector P22 from the inlet pressure transducer.
(22) Disconnect connector P8 from the low oil-level switch.
(23) Disconnect connector P14 from the low oil-pressure switch.
(24) Remove the APU electrical harness (1) from the spring clips at all the rubber grommet locations between connector P13 and the clamp (21).
(25) Disconnect thermocouple terminals B2, B3, B4 and B5 from the thermocouples:
(a) Remove the locknuts from the thermocouple terminal ports.
(b) Remove terminals B2, B3, B4 and B5 from the terminal ports.
(26) Disconnect connector P20 from the Data Memory Module (DMM).
(27) Disconnect connector P18 from the surge control valve.
(28) Disconnect connector P23 from the total pressure transducer.
(29) Disconnect connector P24 from the delta pressure transducer.
(30) Remove the APU electrical harness (1) from the spring clips at all the rubber grommet locations between thermocouple terminals B2, B3, B4 and B5 and the clamp (21).
(31) Remove the bolt (22), nut (24) and clamp (23).
(32) Remove the bolt (20) and the clamp (21).
(33) Remove the bolt (17), spacer (19) and clamp (18).
(34) Remove the screw (25), washer (26), spacer (28) and clamp (27).
(35) Remove the bolt (13), nut (15) and clamps (14) and (16).
(36) Remove the bolt (11), washer (12) and clamp (10).
(37) Remove the APU electrical harness (1).

Subtask 49-15-11-420-050-A ** ON A/C NOT FOR ALL

B. Installation of the APU Electrical Harness
(1) Remove the CAP-BLANKING from each electrical connector and receptacle.
(2) Make sure that all the electrical connections are clean and in the correct condition.
(3) Connect thermocouple terminals B2, B3, B4 and B5 to the thermocouples:
(a) Install terminals B2, B3, B4 and B5 in the terminal ports.
(b) Safety the thermocouple terminal with the locknuts.
(4) Connect connector P20 to the DMM.
(5) Connect connector P18 to the surge control valve.
(6) Connect connector P23 to the total pressure transducer.
(7) Connect connector P24 to the delta pressure transducer.
(8) Install the APU electrical harness (1) on the spring clips in all the rubber grommet locations between thermocouple terminals B2, B3, B4 and B5 and the clamp (21).
(9) Connect connector P13 to the flow divider solenoid.
(10) Connect connector P10 to the ignition unit.
(11) Connect connector P6 to the inlet temperature sensor.
(12) Connect connector P22 to the inlet pressure transducer.
(13) Connect connector P8 to the low oil-level switch.
(14) Connect connector P14 to the low oil-pressure switch.
(15) Install the APU electrical harness (1) in the spring clips at all the rubber grommet locations between connector P13 and the clamp (21).
(16) Connect connector P12 to the load control valve.
(17) Connect connector P26 to the speed sensor.
(18) Connect connector P28 to the oil heater or to the dummy cover-plate connector, if installed.
(19) Connect connector P21 to the IGV actuator.
(20) Connect connector P5 to the oil pump.
(21) Connect connector P9 to the oil pump.
(22) Connect connector P11 to the oil temperature sensor.
(23) Connect connector P15 to the de-oil solenoid.
(24) Connect connector P17 to the low fuel-pressure switch.
(25) Connect connector P19 to the FCU.
(26) Install the APU electrical harness (1) in the spring clips at all the rubber grommet locations between connector P19 and the clamp (21).
(27) Connection of the starter terminals (4), (5) and (6) to the starter motor:
(a) Remove the terminal protector (9), nuts (2) and (8) and washers (3) and (7).
(b) Install the starter terminals (4), (5) and (6) on the terminal studs.
(c) Install the washers (3) and (7) and the nuts (2) and (8) on the terminal studs.
(d) Install the terminal protector (9) on the starter motor.
(28) Attach the APU electrical harness (1) with the clamp (23), bolt (22) and nut (24).
(29) Attach the APU electrical harness (1) with the clamp (21) and the bolt (20).
(30) Attach the APU electrical harness (1) with the clamp (27), spacer (28), washer (26) and screw (25).
(31) Attach the APU electrical harness (1) with the clamp (18), spacer (19) and bolt (17).
(32) Attach the APU electrical harness (1) with the clamps (14) and (16), bolt (13) and nut (15).
(33) Attach the APU electrical harness (1) with the clamp (10), washer (12) and bolt (11).
(34) Connect connector P4 to the generator.
(35) Connect connectors P1, P2 and P3.
(36) Remove the tags from the electrical wiring harness-connectors and terminals.

Subtask 49-15-11-865-051-A ** ON A/C NOT FOR ALL

C. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	APU/APU/CTL	2KD	L42
121VU	APU/ECB/SPLY	1KD	L41

Subtask 49-15-11-710-050-A ** ON A/C NOT FOR ALL

D. Test
(1) Do the ECB self-test (Ref. AMM TASK 49-00-00-710-009).
(2) Do the operational test of the APU (Ref. AMM TASK 49-00-00-710-010).

5. Close-up
Subtask 49-15-11-410-050-A ** ON A/C NOT FOR ALL

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close APU access doors 315AL and 316AR (Ref. AMM TASK 52-41-00-410-001).
(3) Remove the access platform(s).

Subtask 49-15-11-860-051-A ** ON A/C NOT FOR ALL

B. Aircraft Maintenance Configuration
(1) Put the related hydraulic system in the pressurized configuration (Ref. AMM TASK 29-00-00-864-001).
(2) De-energize the ground service network
(Ref. AMM TASK 24-42-00-862-001).
(3) Remove the WARNING NOTICE(S).

[Rev.10 from 2021] 2026.04.01 01:27:29 UTC