GM Service Manual Online
For 1990-2009 cars only

Removal Procedure


    Object Number: 1816292  Size: SH
  1. Disconnect the hybrid battery. Refer to Hybrid Battery Service Disconnect/Connect .
  2. Remove the (12-volt) battery tray. Refer to Battery Tray Replacement .
  3. Caution: To help avoid personal injury, additional precautions must be taken prior to working on the generator control module or the generator starter. After removing the 36V battery cables from the generator battery, remove both engine wiring harness connectors from the generator control module. Wait at least 5 minutes and then remove the generator control module cover. Verify voltage levels at all 36V, 12V, and 3-phase connections, are less than 3 volts using a DMM before proceeding.

  4. Disconnect the 2 engine wiring harness electrical connectors (1) from the generator control module.
  5. WAIT at least 5 minutes in order to allow the voltage stored in the generator control module to discharge.

  6. Object Number: 1816289  Size: SH
  7. Remove the generator control module cover bolts and cover.

  8. Object Number: 1864864  Size: SH
  9. The generator control module will have to be checked for voltage potential using a voltmeter. First, verify that the voltmeter works:
  10. 6.1. Set the voltmeter to DC voltage.
    6.2. Measure the vehicle's 12-volt battery voltage.
    6.3. The meter should read greater than +12 volts DC.
  11. Now, check the generator control module for voltage potential, in order to ensure that the module has been disabled.
  12. 7.1. Measure from the 36-volt positive terminal (3) to a known good chassis ground. The voltage should be less than 3 volts.
    7.2. Measure from the 12-volt positive terminal (4) to a known good chassis ground (2). The voltage should be less than 3 volts.
    7.3. Measure from the ground terminal (2) to a known good chassis ground, checking for continuity.

    Caution: To help avoid personal injury, always treat the 3-phase cable and connectors as if voltage is present and as if the surface of all parts of the cable is hot.

  13. Verify that the generator control module 3-phase cables are disabled.
  14. 8.1. Measure from each phase 1, 2, and 3 connection (1) to a known good chassis ground. The voltage should be less than 3 volts.
    8.2. After verifying that there is no voltage present, the 12-volt and 36-volt positive battery cables can now be removed from the generator control module.

    Object Number: 1831557  Size: SH
  15. Remove the 12-volt positive battery cable nut (1) from the generator control module.
  16. Remove the 12-volt positive battery cable bolt (2) from the generator control module.
  17. Remove the 12-volt positive battery cable from the generator control module.

  18. Object Number: 1831652  Size: SH
  19. Remove the 36-volt positive battery cable nut from the generator control module.
  20. Remove the 36-volt terminal block nuts from the generator control module.
  21. Lift up, and remove the 36-volt terminal block position the block out of the way. Discard the terminal block seal.

  22. Object Number: 1820895  Size: SH
  23. Remove the 36-volt positive battery cable retainer (2) from the shock tower bracket.
  24. Remove the 36-volt positive battery cable bracket nuts (5) from the front of dash studs.
  25. Remove the 36-volt positive battery cable bracket to the front of dash studs.

  26. Object Number: 1820195  Size: SH
  27. From inside the rear of the vehicle, remove the 36-volt positive battery cable shield lead nut (3) from the generator battery.
  28. Remove the 36-volt positive battery cable shield lead (4) to the generator battery stud.
  29. Remove and discard the 36-volt positive battery cable lead nut (6).
  30. Remove the 36-volt positive battery cable lead (5).

  31. Object Number: 1831665  Size: SH
  32. Squeeze the grommet sides together and push the grommet through the floor panel.
  33. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .

  34. Object Number: 1820185  Size: SH
  35. Remove the 36-volt positive battery cable rear suspension bracket bolts.

  36. Object Number: 1820192  Size: SH
  37. Have an assistant support the 36-volt positive battery cable channel.
  38. Remove the 36-volt positive battery cable channel to underbody bolts (1, 2).
  39. With the aid of the assistant, remove the 36-volt positive battery cable channel from the vehicle.
  40. Place the 36-volt positive battery cable channel on a clean work surface.

  41. Object Number: 1831669  Size: SH
  42. Cut the tie straps securing the 36-volt positive battery cable to the battery cable channel.
  43. Remove the 36-volt positive battery cable from the battery cable channel.

Installation Procedure


    Object Number: 1831669  Size: SH
  1. Install the 36-volt positive battery cable to the battery cable channel.
  2. Install NEW tie straps securing the 36-volt positive battery cable to the battery cable channel.

  3. Object Number: 1820192  Size: SH
  4. With the aid of an assistant, position the 36-volt positive battery cable channel to the vehicle.
  5. Feed the 36-volt cable up through the floor panel, and secure the grommet into place.
  6. Notice: Refer to Fastener Notice in the Preface section.

  7. Install the 36-volt positive battery cable channel to underbody bolts (1, 2).
  8. Tighten

        • Tighten the bolts (1) to 22 N·m (16 lb ft).
        • Tighten the bolts (2) to 10 N·m (89 lb in).

    Object Number: 1820185  Size: SH
  9. Install the 36-volt positive battery cable rear suspension bracket bolts.
  10. Tighten
    Tighten the bolts to 25 N·m (18 lb ft).

  11. Lower the vehicle.

  12. Object Number: 1820195  Size: SH
  13. From inside the rear of the vehicle, install the 36-volt positive battery cable shield lead (4) to the generator battery stud.
  14. Install the 36-volt positive battery cable shield lead nut (3) to the generator battery.
  15. Tighten
    Tighten the nut to 6 N·m (53 lb in).

  16. Install the 36-volt positive battery cable lead (5).
  17. Install a NEW 36-volt positive battery cable lead nut (6). Start the nut finger tight, and then torque to the specification given.
  18. Tighten
    Tighten the nut to 15 N·m (11 lb ft).


    Object Number: 1820895  Size: SH
  19. Install the 36-volt positive battery cable bracket to the front of dash studs.
  20. Install the 36-volt positive battery cable bracket nuts (5) to the front of dash studs.
  21. Tighten
    Tighten the nuts to 10 N·m (89 lb in).

  22. Install the 36-volt positive battery cable retainer (2) to the shock tower bracket.

  23. Object Number: 1831652  Size: SH
  24. Install a NEW terminal block seal to the generator control module.
  25. Position and install the 36-volt terminal block to the generator control module.
  26. Install the 36-volt terminal block nuts to the generator control module.
  27. Tighten
    Tighten the nuts to 10 N·m (89 lb in).

  28. Install the 36-volt positive battery cable nut to the generator control module.
  29. Tighten
    Tighten the nuts to 10 N·m (89 lb in).


    Object Number: 1831557  Size: SH
  30. Install the 12-volt positive battery cable to the generator control module.
  31. Install the 12-volt positive battery cable bolt (2) to the generator control module.
  32. Tighten
    Tighten the nuts to 10 N·m (89 lb in).

  33. Install the 12-volt positive battery cable nut (1) to the generator control module.
  34. Tighten
    Tighten the nuts to 10 N·m (89 lb in).


    Object Number: 1816289  Size: SH
  35. Install the generator control module cover and bolts.
  36. Tighten
    Tighten the bolts to 10 N·m (89 lb in).


    Object Number: 1816292  Size: SH
  37. Connect the 2 engine wiring harness electrical connectors to the generator control module.
  38. Install the (12-volt) battery tray. Refer to Battery Tray Replacement .
  39. Connect the hybrid battery. Refer to Hybrid Battery Service Disconnect/Connect .