03/23/26
Message Overview:
Message Name:
RIGHT SPC RELAY FAILED
Message Code:
B3-007849
Associated CAS:
| Reporting LRU: | R WNDW SPC RELAY |
| System Description: | 30-41-00 - Windshield And Side Window Anti-ice |
| Schematic Diagram: | SSM 30-41-00-101 - Windshield and Side Window Anti-Ice |
| Wiring Diagram: | WM 30-41-11 - Windshield Heater Power-Supply (RHS) - ALL |
Message Description:
Right Window Secondary Power Center Relay has failed.
Possible Causes:
- Relay (K66)
- Right Side Window Temperature Controller (RWTC) (A160)
- Right Secondary Power Center (RSPC) (A38)
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin:
- AW300-30-0328 - Windshield Heat Fail CAS Messages
Alert Service Bulletin:
- A100-30-03 - Special Check - Windshield and Side Window Anti-Ice - Torquing of Electrical Connections at Terminal Blocks TB3 and TB4; Ground Studs GS2269, GS2270, GS2273, and GS2274; Windshield Terminals G, H, L1, and L2; and Side Window Terminals P and G
(20501 - 20999)
Full Throttle Blog/Forum Articles/Infoservice/Newsletter: None
Flight Operation Notifications Manual (FONM): None
NOTES:
- The majority of L and R window Temperature Control circuits and parts (including relays) can be used for troubleshooting if needed (interchange).
- The Windshield Temperature Controllers and Side Window Temperature Controllers are different part numbers.
Quick Links:
| General Setup for Maintenance | |
|---|---|
| Standard Aircraft Configuration for Maintenance | AMM 12-00-00-867-803 |
| Connect Electrical Power to the Aircraft | AMM 24-00-00-861-801 |
| Remove Electrical Power from the Aircraft | AMM 24-00-00-861-802 |
| Electrical/Electronic Safety Precautions | AMM 24-00-00-910-801 |
| Electrostatic Discharge Safety Precautions | AMM 24-00-00-910-802 |
| Maintenance Tasks | |
| Removal of the Secondary Power Center (SPC) | AMM 24-62-01-000-801 |
| Installation of the Secondary Power Center (SPC) | AMM 24-62-01-400-801 |
| Removal of the Secondary Power Center (SPC) Relays | AMM 24-62-04-000-801 |
| Installation of the Secondary Power Center (SPC) Relays | AMM 24-62-04-400-801 |
| Operational Test of the Side-Window Anti-Ice System | AMM 30-41-00-710-802 |
| Removal of the Side-Window Temperature Controller | AMM 30-41-05-000-801 |
| Installation of the Side-Window Temperature Controller | AMM 30-41-05-400-801 |
Troubleshooting Recommendations:
- Do the AMM task "30-41-00-710-802 - Operational Test of the Side-Window Anti-Ice System".
- Are the results satisfactory?
- If YES, do close out.
- If NO, continue with the next step.
- Interchange Right Side Window Power Relay (K66) and Left Side Window Power Relay (K65).
- Does the fault "B3-007849 - Right SPC Relay Failed" remain posted?
- If YES, continue with the next step.
- If NO, replace defective Side Window Power Relay and do close out.
- Ensure Right WSHLD/WINDOW PBA (SDS42) is selected ON.
- Measure 28 VDC at Right Side Window Temperature Controller (SWTC) A160P1 pin B.
- Is the 28 VDC present?
- If YES, go to step 9.
- If NO, continue with the next step.
- Check continuity between R SWTC (A160) and R SPC (A38) as per table below:
From To Expected Result Result A160P2 - B A38P2 - Y Continuity A160P1 - K A38P1 - 2 Continuity - If wiring check satisfactory, continue with next step
- If wiring check is not satisfactory, repair wiring and do close out.
- Measure 28 VDC at Right Side Window Temperature Controller (SWTC) A160P1 pin U.
- Is the 28 VDC present?
- If YES, go to step 15.
- If NO, continue with the next step.
- Interchange the Right WSHLD/WINDOW PBA (SDS42) with Left WSHLD/WINDOW PBA (SDS41).
- Does the fault "B3-007849 - Right SPC Relay Failed" remain posted?
- If YES, continue with the next step.
- If NO, replace defective WSHLD/WINDOW PBA.
- Do wiring checks between Anti-Ice Panel (PL19) and Right SWTC(A160) and R SPC (A38). Repair as required.
From To Expected Result Result PL19P2-f A160P1-U Continuity PL19P2-k A38P3-29 Continuity - If wiring check satisfactory, continue with next step
- If wiring check is not satisfactory, repair wiring and do close out.
- Does the fault "B3-007849 - Right SPC Relay Failed" remain posted?
- If YES, continue with the next step.
- If NO, do close out.
- Interchange Right Side Window Temperature Controller (SWTC) (A160) with Left Side Window Temperature Controller (SWTC) (A159).
- If the fault follows the SWTC replace defective Side Window Temperature Controller (SWTC). If fault remain, replace Right Secondary Power Center (R SPC).
- Do close out.