01 Tahoe won't start

Everything on the truck is dead. The keyless doesn't work, the ignition switch does nothing. The battery has a full (12.65 VDC) charge. The battery ground is good. I have checked all the fuses and they are good. i reseated all the relays, still nothing. Partial problem the other day after it rained was the stereo was shutting off by itself. i have isolated the main power running to the amps and that does nothing as well. Please help!!!!!!!
Thanks in advance.

Horn, lites, dash gages? If not look at the ground to the chassis. Or post addt'l info.