Won't crank gas not getting to motor.fuel pump comes on and cuts off,just wont crant.

The security system need to be reset.

Im pretty sure i know what the issue it. Its very common in gm vehicles and i actually had it happen to mine. The security system fails and wont allow the car to start. I searched around and this is the place i got mine from. It was waay cheaper than the mechanic and i did it myself that was 4 years ago and the car still runs to this day. If u have any questions the customer service on the site is amazing and the part is guaranteed :0) Hope this helps ya Good luck

If the fuel pump is working and it won't crank, then it could be your starter. The easiest way to test that yourself is to use jumper cables hooked directly to starter. Yes that can be dangerous if done wrong. If you do, here's some pointers.
1 - Make sure the vehicle is firmly parked, E brake, neutral, wheel blocks, anything to make sure it won't move.
2 - A standard that's in gear will move when the starter turns
3 - The last time I did this I had the drive wheels off the ground, no chance of moving.
4 - hook up the cables to the terminals on the starter first, making sure the cables are not in the way of belts / fans etc. Then connect them to the battery, only briefly, if it cranks, the problem is with a fuse / wire / computer etc. If it doesn't crank, buy a new starter. Hope I helped, Grim