I 'think" I know which panel light you speak of, but let me confirm. it's the part where I'm trying to make it fit into that opening that is driving me nuts, so I can't say I comprehend your comment re the adapter.
I can snap a pic tonight if that would help but check out this URL:
http://www.pfranleds.com/100-series-interior-led-kit/
The LED panels labeled DOME are the ones for the 2nd row and cargo area. Maybe you have a different cargo light but on mine I just popped the panel off, removed the double sided tape from LED panel, plugged it into the adapter (looks like a light, has 2 metal ends and a cord sticking out of it) and plugged the adapter into the normal light posts.

