There is a special tool you can buy for the molex plug pins, but a pointy small Pick tool will get in there and push that tab back so you can pull the terminal out. You can see where you need to poke if you look in there.. Good luck..
The should be key running from side to side pressed in. It has to pop up a little, not much, and then you can release the cilps holding the terminals in. Fought with mine for a while before I figured it out.
Here's the solution . . . (assumes you know to pop the locking tab on the top of the connector - doesn't come up, just lifts up). Once that is done, you can use this picture (pardon the chicken scratch but it was so painful for me, figured I could save someone else some time.
Attached image shows how the terminal (pin) fits into the connector at the back of the 09 RER Radio and how to remove a terminal.