GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2006 🢒 TrailBlazer - 2WD 🢒 Body 🢒 Doors 🢒 Rear Electrical Center or Junction Block Replacement

Removal Procedure

    Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

  1. Disconnect the battery negative cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.
  2. If replacing the rear electrical center on a Chevrolet TrailBlazer EXT or GMC Envoy XL, remove the left second row seat. Refer to Rear Seat Replacement in Seats.

    3. Object Number: 683548 Size: SH
  3. If replacing the rear electrical center on a Chevrolet TrailBlazer or GMC Envoy, position the left second row seat to a cargo position.
  4. Remove the rear electrical center cover.

    5. Object Number: 684302 Size: SH
  5. Remove the battery feed terminal nut (2) from the junction block.
  6. Remove the body control module (BCM) from the rear electrical center. Refer to Body Control Module Replacement in Computer/Integrating Systems.
  7. Fully loosen the 3 bolts (1) that retain the junction block to the electrical connectors.

    8. Object Number: 684301 Size: SH
  8. Release the tabs that retain the junction block to the block base.
  9. Remove the junction block from the block base.

    10. Object Number: 684296 Size: SH
  10. Disconnect the instrument panel harness connector (1) from the junction block.

    11. Object Number: 684303 Size: SH
  11. Disconnect the mobile telephone harness connector (1) from the junction block.

    12. Object Number: 684293 Size: SH
  12. Disconnect the body wiring harness connector (1) from the junction block.
  13. Disconnect the headliner harness connector (2) from the junction block.
  14. Disconnect the console harness connector from the junction block.
  15. Remove the block base retaining nuts from the floor studs.
  16. Remove the block base from the floor panel.

Installation Procedure

    Object Number: 684293 Size: SH
  1. Install the block base to the floor studs.

    2. Notice: Refer to Fastener Notice in the Preface section.

  2. Install the block base retaining nuts to the floor studs.

    3. Tighten
    Tighten the block base retaining nuts to 10 N·m (88 lb in).

  3. Connect the console harness connector to the block base.
  4. Connect the headliner harness connector (2) to the block base.
  5. Connect the body wiring harness connector (1) to the block base.

    6. Object Number: 684303 Size: SH
  6. Connect the mobile telephone harness connector (1) to the junction block.

    7. Object Number: 684296 Size: SH
  7. Connect the instrument panel harness connector (1) to the block base.

    8. Object Number: 684301 Size: SH
  8. Install the junction block to the block base.

    9. Ensure that the retaining tabs are fully seated.


    Object Number: 684302 Size: SH
  9. Install the 3 bolts (1) that retain the junction block to the block base.

    10. Tighten
    Tighten the 3 bolts to 3.5 N·m (31 lb in).

  10. Install the BCM to the rear electrical center. Refer to Body Control Module Replacement in Computer/Integrating Systems.
  11. Install the battery feed terminal nut (2) to the junction block.

    12. Tighten
    Tighten the battery feed terminal nut to 10 N·m (88 lb in).


    Object Number: 683548 Size: SH
  12. Install the rear electrical center cover.
  13. If replacing the rear electrical center on a Chevrolet TrailBlazer or GMC Envoy, position the left second row seat to a passenger position.
  14. If replacing the rear electrical center on a Chevrolet TrailBlazer EXT or GMC Envoy XL, install the left second row seat. Refer to Rear Seat Replacement in Seats.
  15. Connect the battery negative cable. Refer to Battery Negative Cable Disconnection and Connection in Engine Electrical.