2007 Hummer H3 L5-3.7LFACTORY OEM SERVICE PROCEDURE

Fuse Block: Service and Repair



Underhood Electrical Center or Junction Block Replacement

Removal Procedure

1. Open and support the hood.
2. Disconnect the negative battery cable.

Factory service manual diagram



3. Remove the cover (1) from the base (5) of the accessory wiring junction block assembly.
4. Remove the positive battery cable nut (2) and disconnect the cable (3) from the positive terminal stud.

Factory service manual diagram



5. Release the 2 locking tabs from the base side as indicated by the arrows of the electrical center (1), as shown.

Factory service manual diagram



6. Carefully lift at each side of the underhood accessory wiring junction block assembly in order to release the underhood accessory wiring junction block assembly from the 3 main body harness connectors (1) and exposing the lower connectors.
7. Remove the underhood accessory wiring junction block assembly from the vehicle.

Factory service manual diagram




Important: Using a hook-type tool, as shown, re-stage all 3 lower harness connectors into the lower base prior to installing the new underhood accessory wiring junction block assembly.

8. Use the hook tool to pull the connector (1) upward in order to secure the connectors into the base.

Installation Procedure

Factory service manual diagram



1. Verify that all 3 connectors (1) are secured to the base by applying light downward pressure to each connector and verifying the tabs are locked (2) on each side of the connector.
2. Position the new underhood accessory wiring junction block assembly over the top of the base and align the locator pins to the underhood accessory wiring junction block assembly base.
3. Once aligned, apply downward pressure to the new underhood accessory wiring junction block assembly in order to secure the top half to the base.

Factory service manual diagram



4. Inspect the 2 outer locking tabs (1) to ensure the new underhood accessory wiring junction block assembly is locked into the lower base.

Factory service manual diagram




Notice: Refer to Fastener Notice.

5. Install the positive battery cable (3) over the stud and install the retaining nut (2).

Tighten the nut to 10 N.m (89 lb in).

6. Install the underhood electrical center cover (1) to the electrical center base (5).
7. Connect the negative battery cable.
8. Close the hood.

Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.

When to See a Mechanic

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

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

Rather have a pro handle this?

A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.

Comes to youSame-day available12-month warranty
Get a Free Quote

No obligation. See pricing before you book.