I have a 2006 monte carlo and the engine will not crank. I do have an engine light on but codes doesn't pertain to the no start. I had to install a manual starter switch in order to start the vehicle. Any help will be appreciated

 

Not sure if the generation 7 is the same as gen 6 . On gen 6 the fuse box under the hood has a crank or start relay . Other things it could be is the BCM or the ignition switch , I would think if the BCM was bad the security would kick on and the car would shut down . Hopefully others will have some ideas for you . Good luck