Why am I not getting power to the radio on my '94 Plymouth Acclaim?

I've been attempting to install an aftermarket radio to my Acclaim. I bought a wiring harness to make it simple. I wasn't having any luck until I connected the ground wire from the new radio to the black/green wire AND the harness strap. I had it on for a few seconds like this and then turned it off to bolt it into place. Since then, nothing. I checked the fuse, which was fine. Any thoughts?