Failure of the Crossaisle Lights (Floor Proximity Emergency Escape Path Marking System) controlled by EPSU 13WL

TASK 33-51-00-810-845-A
Failure of the Crossaisle Lights (Floor Proximity Emergency Escape Path Marking System) controlled by EPSU 13WL

1. Possible Causes

EXIT MARKER [90WL5]
EXIT MARKER [90WL6]
[361WL3]
wiring
EXIT MARKER [90WL7]
EXIT MARKER [90WL8]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 33-51-00-710-001	Operational Test of the Emergency Lights
AMM 33-51-00-710-007	Operational Test of the Emergency Lighting in the Cabin with the 'LIGHT EMER' Pushbutton Switch
ASM 335104
AMM 33-51-13-000-001	Removal of the Cabin Wall-Mounted Emergency-Exit-Markers
AMM 33-51-13-400-001	Installation of the Cabin Wall-Mounted Emergency-Exit-Markers
AMM 33-51-18-000-001	Removal of the Seat/Wall-Mounted Emergency-Exit Location-Light
AMM 33-51-18-400-001	Installation of the Seat/Wall-Mounted Emergency-Exit Location-Light

3. Fault Confirmation

CAUTION: DO NOT USE THE TEACH-IN PROCEDURE AS AN ALTERNATIVE FOR TROUBLESHOOTING. A TEACH-IN PROCEDURE IS NOT A RESET PROCEDURE. BEFORE YOU DO A TEACH-IN PROCEDURE, MAKE SURE THAT YOU CORRECTED ALL FAILURES. IF YOU DO NOT OBEY THIS, FAILURES CAN CAUSE A MALFUNCTION OF THE CABIN EMERGENCY LIGHTING SYSTEM.

Subtask 33-51-00-710-135-A ** ON A/C NOT FOR ALL

A. Do the operational test of the emergency lights with the MCDU AMM 33-51-00-710-001.

4. Fault Isolation
Subtask 33-51-00-810-144-A ** ON A/C NOT FOR ALL

A. If the test gives a different maintenance message, do the trouble shooting procedure related to the maintenance message.

Subtask 33-51-00-810-145-B ** ON A/C NOT FOR ALL

B. If the operational test gives the maintenance message:
(1) FPEEPMS CROSSAISLE LT/EPSU(13WL)AFT L:

do the Operational Test of the Emergency Lighting in the Cabin by Pushbutton Switch AMM 33-51-00-710-007.
during the test monitor the EXIT MARKER [90WL5] , EXIT MARKER [90WL6] , and the [361WL3] ASM 335104.
replace the EXIT MARKER [90WL5] AMM 33-51-13-000-001 and AMM 33-51-13-400-001 if not illuminated.
replace the EXIT MARKER [90WL6] AMM 33-51-13-000-001 and AMM 33-51-13-400-001 if not illuminated.
replace the [361WL3] AMM 33-51-18-000-001 and AMM 33-51-18-400-001 if not illuminated ASM 335104.

(a) If the fault continues and:
1 The EXIT MARKER [90WL5] is not illuminated:

do a check and repair the wiring between:
lamp module 90WL5 pin 3 and EPSU 13WL pin -H.
lamp module 90WL5 pin 1 and GND ASM 335104.

2 The EXIT MARKER [90WL6] is not illuminated:

do a check and repair the wiring between:
lamp module 91WL6 pin 3 and EPSU 13WL pin -H.
lamp module 91WL6 pin 1 and GND ASM 335104.

3 The [361WL3] is not illuminated:

do a check and repair the wiring between:
lamp module 361WL3 pin 3 and EPSU 13WL pin -H.
lamp module 361WL3 pin 1 and GND ASM 335104.

Subtask 33-51-00-810-145-E ** ON A/C NOT FOR ALL

B. If the operational test gives the maintenance message:
(1) FPEEPMS CROSSAISLE LT/EPSU(13WL)AFT L:

do the operational test of the emergency lighting in the cabin by pushbutton switch AMM 33-51-00-710-007.
during the test monitor the EXIT MARKER [90WL7] and the EXIT MARKER [90WL8] ASM 335104.
replace the EXIT MARKER [90WL7] AMM 33-51-13-000-001 and AMM 33-51-13-400-001 if not illuminated.
replace the EXIT MARKER [90WL8] AMM 33-51-13-000-001 and AMM 33-51-13-400-001 if not illuminated ASM 335104.

(a) If the fault continues and:
1 The EXIT MARKER [90WL7] is not illuminated:

do a check and repair the wiring between:
lamp module 90WL7 pin 3 and EPSU 13WL pin -H.
lamp module 90WL7 pin 1 and GND ASM 335104.

2 The EXIT MARKER [90WL8] is not illuminated:

do a check and repair the wiring between:
the lamp module 90WL8 pin 3 and EPSU 13WL pin -H.
the lamp module 90WL8 pin 1 and GND ASM 335104.

Subtask 33-51-00-710-136-A ** ON A/C NOT FOR ALL

C. Do the test given in Para. 3.

5. Close-up
Subtask 33-51-00-860-101-A ** ON A/C NOT FOR ALL

A. Put the aircraft back to its initial configuration.

[Rev.8 from Aug 2018] 2026.04.04 04:32:10 UTC