Rain leaked in roof, now too cold to dry out.
 

Hi folks. 05’ H2 base (275,000 miles)
Water dripped in and shut truck down to no power.
weeks ago, I had water getting in there and then it finally dried out and the truck started right up when the weather was warmer.
After I tried to seal up the marker lights,(silicone), it was driving OK for about two weeks. Then I drove it to the grocery store on a cold wet night, and it completely went dead after trying to start it. Had to have it towed, which was a nightmare because it was unable to be put into neutral.

Other symptoms now. My key will pull straight out of the ignition, but the ignition will not go back to off position. It stays in accessories, or you could attempt to try to start it. However, there is no power, and it has been so cold out that I have not been able to warm it up inside enough to take care of the possible problem.

I’ve read about the BCM being damaged, but it’s hard to say because there’s no warnings of that pinpointing the problem.

my question is: what part of the truck would make the ignition not go back to the off position. What do you all think is ruined from getting wet? Dried out and warmer weather, I believe the truck may start. (No garage here). Thanks for any replies.

Update:
 

I stuck the space heater in there to try to warm everything up and while waiting, I tried to troubleshoot a few other ideas and I wiggled the negative battery cable around and the power came on.

So I think I got a pinpointed that there’s either a loose wire, ground or oil on the negative connection. After I wiggle it, and try to start it, the power goes back dead again. Repeat procedure and it power on, but will not attempt to start or crank. It’s too damn cold here to mess with it now.

Open the driver's door, and pop the door sill plate up. It simply snaps in place. See if you have an inch or two of water pooled under it. It will submerge part of the wiring harness that travels through there..... If your carpet feels damp under the driver side floor mat, that's a good indicator that they're standing water under that door sill. The sound deadening under the carpet acts like a sponge and we'll keep the carpet wet.

Sounds like your lock cylinder is acting up if it won't turn all the way off. The electrical portion of the switch, the actual ignition switch, plugs into the underside of the lock cylinder. It's basically a plastic gear moving electrical contacts. Both are suspect, I would probably replace both due to the high mileage. And as usual check all ground connections, as well as the battery positive connections.

Sounds like you need to replace the negative battery cable. "After I wiggle it, and try to start it, the power goes back dead again" that is a common symptom of a bad connection, possible either end of the negative cable or the cable itself. Charge the battery, load test, check the cables. First step of any electrical diagnosis.