2000 Silverado Electrical?

I have a 2000 Silverado and at very random times all the gauges except for the voltmeter go to zero and then go back to normal. When this happens, the battery icon appears in the message center and the air bag light, ABS, and service engine soon light comes on. When the gauges go back to normal, all the other lights turn off. I found some other threads that have this same problem. I checked the battery and alternator, they are fine. Checked all grounds in engine compartment, battery, frame, block, etc. and no problem. Checked fuse box for corrosion and what not. Ground behind instrument panel? I know theres a whole lot of wire back there but that's my next guess. What should I be looking for?

The same lights come on when it acts up as when you start the truck, well right before you start it. Could it be something with the ignition or ignition switch? How to I test that?
Thanks

I had the same problem, also caused some Transmission problems. Ignition Switch replacement fixed everything.