Remove the plastic panel in the rear corner.
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This is held in place by four plastic rivets. Three of them are visible in the picture. I'm sure you can find the fourth on your vehicle. Remove the rivets by securing the outer portion in place while prying the center outward 0.25"-0.5" with a small screwdriver. The rivets will remove as whole pieces. Don't damage them because you'll need them for reassembly.
