Engine will not crank over?

I would try to put the vehicle in neutral and try to crank it over, if it cranks over the gear range sensor is bad. Here is a guide that can help us, and I have included the starter wiring diagrams to help us see how the system works.

https://www.2carpros.com/articles/starter-not-working-repair

There is a crank fuse and a crank relay I would check or swap out, here are guides that can help and I also have included the fuse and relay locations.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

and

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Check out the images (below). Let us know what happens and please upload pictures or videos of the problem so we can see what's going on.

I tested the crank fuse and relay they are both good, I put the Hummer in Neutral and still no good. had the Battery check and it is good still don't know what to do .

Does it make any noise at all when trying to crank over? Please upload videos of the problem so we can see what's going on. You may have a locked-up engine. Also did you check for power at the trigger wire when trying to crank the engine over?

I checked all the fuses under the hood, and it was the PCM B 20-amp fuse. The truck fired right up thanks for your time.

Thanks for letting us know, we are here to help, please use 2CarPros anytime.