# SDR CALA2026040715131

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: April 5, 2026
- Submitted: April 7, 2026
- Operation: Air carrier
- Aircraft: [N17421](https://openairdocs.org/aircraft/N17421), registered now
- Make and model: Boeing 737-9
- Registry model: [Boeing 737-9](https://openairdocs.org/model/boeing-737-9) (OpenAirDocs)
- Aircraft serial: 67744
- Aircraft time: 813 hours, 280 cycles
- System (JASC): [5270 · Door Warning System](https://openairdocs.org/jasc/5270)
- Part: Proximity Switch
- Part number: 285A1600102
- Part serial: F10858
- Condition: Faulted
- Location: Zone 200
- Part time: 812 hours, 279 cycles
- Stage of operation: TO
- How discovered: O
- Nature of condition: N
- Precautionary procedure: C
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/CALA2026040715131

## Discrepancy

LEFT FWD AND AFT OVERWING EXIT LIGHT ON,  ON PWR ADV ON TO FADED.  DIFFICULTY EXTRACTING WIRES FROM CONNECTOR WITH WIRES PULLERS.  R & R PROXIMITY SWITCH  ELECTRONICS UNIT IAW AMM 32-09-10-400-801. LRU REPLACEMENT TEST STILL SHOW FAIL.  DURING REMOVAL ONE BOLT/NUTPLATE WAS DAMAGED.  PERFORMED WIRING TROUBLESHOOTING IAW SSM 52-71-13-102.  INITIAL VOLTAGE CHECK OF PSEU PLUG D10986 PIN 40 SHOWED NO VOLTAGE. CONTINUITY CHECK FROM PIN 40 TO X2 OF RELAY R742 SHOWED GOOD CONTINUITY.  PERFORMED VOLTAGE CHECK AT X1 OF RELAY SOCKET & VOLTAGE WAS GOOD.  REINSTALLED RELAY R742 & VOLTAGE WAS NOW GOOD AT PSEU PIN 40. REINSTALLED CONNECTORSS ON PSEU & PERFORMED POWER ON CHECK OF PSEU IAW AMM 32-09-10-710-801 LRU REPLACEMENT.  SYSTEM TEST PASSED.   REPLACED RELAY IAW AWM 73-22-31. DURING OPS TEST OF PSEU FOR R737 CHANGE TEST FAILED WITH MX MSG 52-76017. MX PERFORMED POWER ON CHECK OF PSEU IAW AMM 32-09-10, LIGHT INDICATION ON IN THE COCKPIT.

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