# SDR SWAA2022120677988

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: December 2, 2022
- Submitted: December 6, 2022
- Operation: Air carrier
- Aircraft: [N7820L](https://openairdocs.org/aircraft/N7820L), registered now
- Make and model: Boeing 737-79P
- Registry model: [Boeing 737-79P](https://openairdocs.org/model/boeing-737-79p) (OpenAirDocs)
- Aircraft serial: 28253
- Aircraft time: 57,005 hours, 36,779 cycles
- System (JASC): [2197 · Air Conditioning System Wiring](https://openairdocs.org/jasc/2197)
- Part: Ground Wire
- Condition: Failed
- Location: Outflow Valve
- Stage of operation: CL
- How discovered: O
- Nature of condition: J
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/SWAA2022120677988

## Discrepancy

BOTH AUTO PRESSURIZATION CONTROLLERS FAILED, PRESSURIZATION NOT CONTROLLABLE IN MANUAL MODE.  R & R  AFT OUTFLOW VALVE IAW AMM 21-31-03. OPS CHECKED FAILED ON PRESSURE CONTROL MODULE 2 BITE CHECK.  CHECKED WIRES BETWEEN D10740A & D10734 OF OUTFLOW VALVE IAW FIM 21-31, TASK 805. FOUND ALL WIRES CHECKED HAVING CONTINUITY.  SWAPPED PRESSURE CONTROL MODULES 1 & 2, SAME FAULT STAYED ON NR 2.  FOUND NO GROUND AT CONTACT SMALL B- OF CONNECTOR D10734 ON OUTFLOW VALVE.  TERMINATED THE WIRE W6204-5505-20 & INSTALLED PIN INTO GD3740-DC IAW SWPM 20-90-15. INSTALLED THE OUTFLOW VALVE IAW AMM 21-31-03. PERFORMED BOTH MANUAL MODE TEST & CABIN PRESSURE CONTROL SYSTEM GROUND TEST PER AMM 21-31-00. NO FAULTS NOTED.

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