Kinda same problem as Gomer. But it is getting worse. 2007 Silverado. Intermittently when I turn the key the starter doesn't engage. It will or always has, after a few minutes fired right up. Remote start doesn't work either when it won't crank. I tried beating and wiggling on things and I discovered that if I don't do any thing it will start in a bit. I've swapped starter relays and no change. I don't get the security light coming on that youtube seems to know how to fix. I'm thinking ignition switch because it seems like operating the key will make it start sometimes but that is probably just coincidence. So I am entertaining yall's wild ass guesses. If it would stay broke I could find it. Looks like ignition switch is easy enough to replace I may just give that a whirl unless somebody else has a better idea.

Maybe an anti-theft problem, not recognizing the key. You might try locking and unlocking the doors. I have seen the wires from the ign.switch to the anti-theft break and only make contact sometimes. They move every time you turn the key. Does it have a small 4 pin start relay in the fuse box under the hood? Do you hear the fuel pump come on and prime up when you turn the key? Does it have an anti-theft light that comes on with the key when it does start? Chasing down intermittent problems in newer automobiles can be time consuming.

I have two different keys does it on both of them. I swapped the relays. I can't hear the pump because usually I am by myself when it happens. Anti theft light does not come on. Didn't think about unlock/locking doors but will try that.

Have you tried putting fire directly to the starter? Just to eliminate it.

There is a recall on some Chevy/GMC trucks due to a faulty ignition switch. I don't know the details of it, but yours may be in the recall timeframe

That wasn't trucks.

My 3500HD is included in it (mine's an '11 though...called to make an appt to get my airbag recall taken care of last week and they said the ignition switch recall also applied). GM did the mid-year change on the trucks in 07 (GMT800 to GMT900)...if you have the early 07 model (old body style), it probably doesn't pertain to it

Hmmm...mine is new body style. Need to make a call I guess.

Old post but I fixed it. Took battery cables off and shorted them together for 30 minutes. It is back like it used to be. I had just disconnected the battery and left it loose a couple hours. Shorting them together did the trick and rebooted every thing. FYI in case you have one doing stupid stuff.

Glad you got it figured out.

Been doing that for years on different vehicles. I have 4 or 5 wires laying around with alligator clips on both ends that I use. Only takes 5 minute's to drain the capacitors in the computer. It takes about 10-12 hours to drain the capacitors if you just remove the cables. A few hours is not enough time to drain the capacitors. I call it a cold rebooting..

thanks for the update I had a cadillac that did this for a decade. still made it over 200k and iam ready to take it to the junk yard now but for a bad computer maybe i will try this for that issue as well.