Crank no start, security light turns on?

Is the security light flashing? does the engine run on starting fluid? Also, we should run the codes to see what comes up.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

and

https://www.2carpros.com/articles/car-not-running-advanced

Do you hear the fuel pump kick on when you turn the key on but not crank the engine over? Please go over these guides and get back to us.

The security keeps flashing when you try to crank the truck. I can hear the fuel pump coming on.

What is the normal fuel pressure supposed to be? because ours is between 20 and 40 PSI.

It looks like you found the problem, here is the fuel pressure stats:

Key On Engine Off .................... 60-66 psi

Here is how to change the fuel pump out. Check out the images (below). Please let us know what happens.