In a H3 2007, there are three main fuse boxes located at different areas of the vehicle. Here are the details on the location of each fuse box:

1. Underhood Fuse Box - The primary fuse box is located under the hood of the vehicle, on the driver's side. To access it, open the hood and look towards the back left corner. You will see a black plastic box with a removable lid. This fuse box contains fuses for various components including the engine, cooling fan, ignition system, and more. The lid should have a diagram indicating the function of each fuse.

2. Instrument Panel Fuse Box - The second fuse box is located on the driver's side of the instrument panel, towards the lower left side. To access it, you'll need to open the driver's side door and remove the panel on the side of the dashboard. Once removed, you will see a rectangular fuse box. This fuse box contains fuses related to various electrical components inside the vehicle such as the interior lights, power windows, radio, and more. Again, a diagram on the lid or inside the fuse box cover should indicate the purpose of each fuse.

3. Rear Fuse Box - The third fuse box is located in the rear cargo area of the vehicle. To access it, open the rear door or tailgate. Towards the right-hand side, there should be a removable panel. Remove the panel, and you will find a smaller rectangular fuse box. This fuse box contains fuses related to the rear lights, rear wipers, rear defogger, and other components in the back of the vehicle. Refer to the diagram provided on the lid or inside the fuse box cover for the function of each fuse.

Please note that these descriptions are general guidelines based on the typical location for the fuse boxes in a H3 2007. However, it's always recommended to consult the owner's manual for your specific vehicle to ensure accurate information and diagrams for your particular model.