99 Tahoe shuts off while driving

I have a 99 Tahoe that keeps shutting off while driving. By that I mean its just like someone turned the key off. The motor quits running, radio shuts, off, A/C shuts off, etc. Just like you turned the key off. But it starts right back up!! I had the shop check it out and they did'nt get any codes and told me there was nothing wrong with it. However with wife and kids driving down the freeway I cant have it shutting down all the time!!!!! Any Ideas??

You might have a loose battery connection, corroded battery cables, loose or bad ground wire. If its one of these, when the radio comes back I doubt it would have the correct time. It may even be a problem with your ignition switch, wiring or fuses under the hood(check IGN fuses)

I had a loose battery cable once on a Range Rover and it was acting like demons had taken over. Alarm system was triggered, horn blowning, lights flashing ...

It was loose at the starter solenoid.

Whats the best way to trouble shoot the ignition switch? I replace the battery about 3 weeks ago and there was some corrosion on the cable that I cleaned up!

WS,

So the clock and other non-ignition items still working, right ?

I would check schematic and measure voltage on circuits by probing selective fuses in the fuse box under the hood. It's intermittent so it will be tough to catch it. If I got desparate I would solder or clip (with fuse) a wire and run it into passenger compartment and hang my meter of it (lay on dash). Use a primary circuit like ECU feed.

I have disassbled steering column covers it the past and measured at the ignition switch also.

There probably is a fuse ahead of the ignition switch also, so check the feed to the switch.

If you are sure everything related to ignition is going off, I would say the switch is likely. I don't assume before throwing part, I verify before replacing anything.