Where is the wiring harness and opening to change bulbs? It seems sealed off from the trunk.

 

Remove the black plastic wing nuts inside trunk then remove tail light assy

 

I took them off and the nuts and washers. That thing is sealed on very tight. The screwdriver I tried to pry on it with just bent metal. I did find the wire bundle to tie the trailer lights into and there was a cannon-type connector. All this was on the lower left side of the trunk. The wire color code is what is stumping me now. It does not match the wire colors of the lights.

 

Yes it does brown green & yellow White is body ground .Your best investment would be a 12 volt test light

 

OK. I finally got it. The wing nuts are in the inside of the trunk and the assy comes off from the outside. But that still does not help with getting to the back up lights. Any ideas?

 

Ok...back up lights can be gotten to underneath the car..