I think I have Theft lock problems

[MaxFarmer]

Truck will start and run for maybe 2-3 seconds and then shuts off. Repeatedly. Doesn’t matter if I cycle the key off/on or just leave it on and crank again. I believe it’s something theft lock related because after it shuts off the dash light of a car with a padlock on it flashes. It’s solid lit for the few seconds that the truck is running.
I’ve tried locking and unlocking the doors a few times with the FOB, and all it’s functions still seem to work.
I can’t recall if the theft lock sensor is in the key itself or the FOB?
Thanks in advance!
Jason

 

[duramax on fire]

If it's like mine it's in the cylinder. Cylinder sends proper ohms to ecm to start truck. This was on a gasser. Google key relearn procedure. Actually I think it's a sticky here somewhere. Also check battery cables. Loose or not.

 

[MaxFarmer]

Ok I will try that. Thanks!
For what it’s worth, a few weeks ago the truck started doing this thing where it won’t even turn over if the steering wheel isn’t pretty much raised all the way up or down. Won’t even turn over in the middle settings. Maybe now it’s all steering column related?

 

[2004LB7]

Probably a break in the wiring. I would start there

 

[MaxFarmer]

Turns out there was a connector basically unplugged inside the steering column. Under the key cylinder.
I was poking some of the wiring harnesses inside the column while waiting on relearning the key and lost all power. Tore column covers off and found that connection basically “loose”. It appears to me that whatever is supposed to “keep” that connector connected has been broken off sometime in the past.
Thanks for leading me to the right places!:hug: