How do I open the subwoofer compartment on a 2000 Mercury Mountaineer/Ford Explorer?

You have to remove the entire rear trim panel from the rear door to the hatch. The cover over the subwoofer is plastic riveted (melted) to the trim panel at the factory and is not meant to come apart from the trim panel, if you do, it will not go back into place. Remove the rear seat belt , and remove the entire trim panel to get to the speaker.

Remove the quarter trim panel; refer to Section 501-05.

Remove the subwoofer.

Disconnect the electrical connector.

Remove the screws.

Remove the subwoofer.

That is the directions,minus pictures,from the Ford technicians website.I'll repost when I find section 501

If equipped, remove the retractable cargo cover.

Remove the liftgate scuff plate (13144).

Starting at either end and working along the liftgate scuff plate, use Windshield and Molding/Trim Removal Kit to remove the scuff plate.

Remove the liftgate scuff plate.

If equipped, remove the rear power lock switch assembly.

Disconnect the electrical connector.

Remove the B-pillar trim panel. For additional information, refer to Trim Panel—B-Pillar.

Remove the three rear quarter trim panel screws.

Position the carpet aside to gain access to the screws.

Remove the rear safety belt anchor nut.

Open the rear safety belt guide bolt cover.

Using the special tool, remove the rear safety belt guide bolt.

Remove the quarter trim panel (31012).

Remove the pin-type retainers.

Feed the safety belt webbing through the opening in the quarter trim panel.

Remove the quarter trim panel.

Installation

Install the quarter trim panel.

Feed the safety belt webbing through the opening in the quarter trim panel.

Position the quarter trim panel.

Install the pin-type retainers.

Using the special tool, install the rear safety belt guide bolt.

Close the rear safety belt guide bolt cover

Install the rear safety belt anchor nut.

Install the three rear quarter trim panel screws.

Install the B-pillar trim panel. For additional information, refer to Trim Panel—B-Pillar.

Install the liftgate scuff plate.

Position the liftgate scuff plate.

Start at either end and work along the liftgate scuff plate, pushing it into the floor panel.

If equipped, install the retractable cargo cover.

That is copied and pasted from tech site for 501.05