Lights, radio, everything work fine. It just wont turn over?

Hello, if this is an automatic, have you tried cranking in neutral? There should be a starter relay in the fuse box under the hood, you can do some testing there, just make sure the tranny is in park or neutral. When the problem occurs, unplug the relay, on the relay terminals use a test lite, with the key in the crank position, two terminals should be hot.

I haven't looked at the theft info on your vehicle, you don't have a theft lite flashing?

Are you saying, when the problem occurs, the starter won't crank? If so, you have to check the starter circuit, when the problem is ongoing. Intermittent problems can be a pain to track down. I can't tell much without testing.

You will have to do some testing, when the problem is ongoing. The purple wire at the starter solenoid S terminal should be hot with key in the crank position. If it isn't hot we'll have to backtrack the circuit. In the diagram for the relay, you see the line with the arrowhead on it, top, When the relay is energized, that line switches to the purple wire. The other, left side on top, is voltage to the coil side of relay, goes hot with key in the crank position, is wired through the neutral or clutch switch, depending on tranny. The yellow wire, bottom left is ground for the coil side of relay, grounded by the pcm.

You can use a testlite to check voltage. You can use a remote starter button, just to see if starter will crank. You have to hook it up to starter solenoid. If you use a starter button, hopefully the leads are long enough to get you out from under the vehicle, in my experience, the leads aren't long enough. Make sure the tranny is in park or neutral and a functional ebrake is set.

Another test, when problem is ongoing, is to turn on the headlamps, turn key to crank, do the headlamps dim--go out--stay bright no reaction? Let us know what you find.