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HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4.2 S, 4WDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 1793 (HYBRID CONTROL SYSTEM)REPAIR INSTRUCTIONSGENERATOR CONTROL MODULE 3-PHASE CABLE ASSEMBLY REPLACEMENTREMOVAL PROCEDURE
2003 Chevrolet TrailBlazer 4.2 S, 4WD

Removal Procedure

2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Removal Procedure
WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
    Fig 1: View Of Engine Wiring Harness Auxiliary Bussed Electrical Center (BEC)
    GM1813960Courtesy of GENERAL MOTORS CORP.
  1. Disconnect the hybrid battery. Refer to Hybrid Battery Service Disconnect/Connect .
  2. Remove the air cleaner outlet duct. Refer to Air Cleaner Outlet Duct Replacement .
  3. Remove the drive belt. Refer to Drive Belt Replacement .
  4. Remove the engine wiring harness auxiliary bussed electrical center (BEC) (1) from the wiring harness relay block bracket.
  5. Remove the engine wiring harness clip (2) from the positive battery cable bracket.
  6. Reposition the engine wiring harness auxiliary BEC (1) out of the way.
    7. Fig 2: Underhood Bussed Electrical Center (UBEC)
    GM1814045Courtesy of GENERAL MOTORS CORP.
  7. Remove the underhood bussed electrical center (UBEC) cover (1).
  8. Loosen the UBEC bolts (2), once loose, tap the bolts once, in order to disengage the bolt from the electrical connectors.
  9. Disengage the UBEC retaining tabs on the 4 corners and remove the UBEC.
    10. Fig 3: Forward Lamp Wiring Harness Clips And Ubec Electrical Connector
    GM1814035Courtesy of GENERAL MOTORS CORP.
  10. Remove the forward lamp wiring harness clips (2) from the positive battery cable bracket.
  11. Remove the forward lamp wiring harness UBEC electrical connector (1) from the UBEC bracket and secure out of the way.
    12. Fig 4: View Of Clip And UBEC Connector
    GM1814036Courtesy of GENERAL MOTORS CORP.
  12. Remove the engine wiring harness clip (2) from the battery tray.
  13. Remove the engine wiring harness UBEC electrical connector (1) from the UBEC bracket and secure out of the way.
    14. Fig 5: Forward Lamp Wiring Harness Electrical Connector And UBEC Electrical Connector
    GM1814033Courtesy of GENERAL MOTORS CORP.
  14. Remove the forward lamp wiring harness electrical connector (2) from the battery tray.
  15. Remove the body wiring harness UBEC electrical connector (1) from the UBEC bracket and secure out of the way.
    16. Fig 6: Clips And Bolts
    GM1820891Courtesy of GENERAL MOTORS CORP.
  16. Remove the 12-volt positive battery cable clips (4) from the UBEC bracket.
  17. Remove the 12-volt positive battery cable clip (3) from the positive battery cable bracket.
    18. Fig 7: UBEC Bracket And Bolts
    GM1814038Courtesy of GENERAL MOTORS CORP.
  18. Remove the UBEC bracket bolts (1) and bracket.
    19. Fig 8: Identifying Forward Lamp Wiring Harness Electrical Connector
    GM1813958Courtesy of GENERAL MOTORS CORP.
  19. Remove the forward lamp wiring harness electrical connector (1) from the positive battery cable bracket.
    20. Fig 9: Bracket And Nut
    GM1816288Courtesy of GENERAL MOTORS CORP.
  20. Remove the air conditioning compressor and condenser hose nut (1) from the generator control module bracket stud.
  21. Remove the positive battery cable bracket (2) from the stud.
    22. Fig 10: Battery Hold Down Bracket And Retainers
    GM1813962Courtesy of GENERAL MOTORS CORP.
  22. Remove the battery hold down bracket nuts (1, 4).
  23. Remove the wiring harness relay block bracket nut (3) and bracket (2).
  24. Remove the battery hold down retainer (5).
    25. Fig 11: Generator Control Module Bracket, Bolts And Stud
    GM1815938Courtesy of GENERAL MOTORS CORP.
  25. Remove the generator control module bracket bolts and stud.
  26. Remove the generator control module bracket.
    27. Fig 12: 3-Phase Voltage Cable Bracket And Bolt
    GM1810869Courtesy of GENERAL MOTORS CORP.
  27. Remove the generator control module 3-phase cable bracket to tie bar bolt.
    28. Fig 13: Engine Wiring Harness Electrical Connectors
    GM1816292Courtesy of GENERAL MOTORS CORP.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.