2006 Monte Carlo LT 3.9L

Drove the car home from work yesterday afternoon, everything has been fine. Went out to start it a few hours later and the key fob wouldn't unlock the door, lights didn't come on, etc. Stuck the key in the ignition and turned it, nothing. Not even a click.

Now the key is stuck in the ignition but the car won't start. I replaced the battery, it was dead. I pulled the console out and the black wire for the interlock solenoid was loose in the connector. Shifter is stuck in park unless I use the manual button on the side. I noticed when I push on the brakes the brake lights do not come on. I tried it with the key turned on as well. Is that normal?

I checked the wires to the connector for the solenoid. The black and the purple and white are grounded. The green and white gets just over 2 volts, the yellow has no power and isn't grounded. Should the yellow have power?

The car not starting and the brake lights not coming on confuses me. With a battery I know is good the car is still doing the same thing as before. Key stuck, won't start even with the shifter in neutral and the shifter won't move unless I press the button on the side.

I checked the BCM and RAP fuses, they are fine. The headlights, dash lights, AC fans and radio work. The turn signals, door locks and windows do not work. When I turn the key on acc the display reads Traction Control Off and then switches to Service Tire Pressure Monitoring System and stays there. There is also no highlighted box around the shifter position in the driver information center. When I try to start it, I can hear a click but the engine does not turn over.

Does anyone have any ideas?

Thanks in advance for any help.