Power source not putting out!

I have an 88 gmc jimmy and I pulled out the stock radio to put in a kenwood. I've had problem after problem (first time doing this). My biggest problem is that the factory yellow power output wire is no longer putting out power. It did when I first pulled the radio, but now it no longer does. It's literally just been sitting in my driveway.

What could cause this to happen!? What are my options now for delivering power to my stereo?

you blew a fuse somewhere ... look in the fuseblock under the dash AND the one under the hood