Service difficulty report · Wire Harness · Boeing 7878

Difficulty date
April 17, 2026
Submitted
April 20, 2026
Operation
Air carrier
Aircraft
N29907
Make and model
Boeing 7878
Aircraft serial
34830
Aircraft time
51,950 hours, 6,345 cycles
Part
Wire Harness
Condition
Faulted
Location
Zone 200
Stage of operation
IN
How discovered
O
Nature of condition
J
Precautionary procedure
K

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

FOUND FLOOR PROXIMITY LIGHT WIRE BROKEN AT TEMINAL (AIRCRAFT SIDE) SEAT 30D. RETERMINATED CONTACTS AND REPLACED FLOOR PROXIMITY LIGHT, REF AMM 33-51-06. NO HELP. FLOOR PROX LIGHT AT 30D STILL INOP. EMERGENCY LIGHTS GND TEST FAILED. MX MSG: 33-11624 EMERGENCY LIGHTS ARE OUT AT MIDDLE ROWS 30-31 AND 32 BOTH LT & RT. DISCONNECTED GROUND PROX LIGHTS INDIVIDUALLY IN ALL AFFECTED ROWS, NO HELP, RELOADED WELS OPS SOFTWARE REF AMM 33-51-07, NO HELP. CORRELATED FAULT IS FOR WELS UNIT 24, SUSPECT WELS CONTROL UNIT 24.2 FAILURE. REPLACED WIRELESS EMER LIGHT CONTROL UNIT 24.2 AT ROW 22, IAW M M33-51-07-01A-, NO HELP SEAT SIDE MARKER AT ROW 30, 31, 32 BOTH ISLES ARE STILL INOP. TRIED TO RECREATE THE FAULT BY DISCONNECTING THE WIRE HARNESS THAT GOES FROM REMOTE WCU 24.1 TO SEAT ROWS 30 THRU 32 & FOUND SIMILAR RESULTS TO EMERGENCY LIGHTS NOT ILLUMINATING. SUSPECT BAD WIRING BETWEEN CONTROLLER AND FLOOR PROXIMITY LIGHTS. REF IPC 25-25-02-51B-941A ITEM NUMBER 215 P/N 8-2157015-1. BAD HARNESS IS LOCATED BETWEEN ROW 22 AND ROW 30, CENTER SEAT GROUP, THE LT SEAT TRACK. FOUND LEFT SEAT TRACK CONNECTOR AT ROW 30 NOT FULLY SEATED, RESEATED CONNECTOR AND LIGHTS AT 30F, 31D/F, AND 32D/F NOW OPS. FOUND WIRE TERMINATIONS AT 30D EMERGENCY LIGHT TO BE REVERSED, RETERMIN POLARITY AND REPLACED FLOOR PROX LIGHT AT 30D IAW AMM 33-51-06. ALL PREVIOUSLY STATED INOP LIGHTS NOW OPERABLE. OPS CHECKS OK

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