There's better videos out there to explain this, just google. To remove the pin from the harness pry the lock up a little and stick a sewing needle in the radio side of the plug in the hole associated with the pin hole you're trying to free up. This will push the pin's locking mechanism down and make it easy to remove the pin, without trying to rip it out by the wire like this guy did. Pulling it out by the wire is very risky. Other than that just make sure you have a good ground. Should work fine.
-Mike
P.S. While you're at it you may want to go ahead and install the 5v regulator i
