I have some
very long and
very thin needle nose pliers I use to get the job done, but a thick needle or pick is going to work. Those eyeglasses screwdrivers work well I hear. Like Luka said, you need to push the needle into the back of the harness plug (where the wire enters) above the wire on the top of the wire pin. While pushing in, the needle will push a plastic latch out of the way. You need to pull the pin out at the same time that you keep the needle pushed into the top of the pin hole.
Good luck.