I foolishly bought a stereo for my daughter's car at Crutchfield, instead of a local shop that does installations. This may not sound hard to all of you, but I can't figure out how to remove the one heavy black wire which I'm assuming is the ground. I figured out how all the other harnesses come off, and the antenna wire. The black wire has a clip of some sort over it, which I pried out the side tabs and got the top of the clip to sort of flip up. I pulled on the wire, but not too hard--I'm afraid of damaging it. Please help if you can--things have changed a lot since the last time I put a car stero in!