Won't start

Make sure the battery has a full charge and battery connections all good. I haven't looked to see if your security system has anything to do with your starter motor? Then, if it cranks good but won't start, have a helper crank it while you check for spark at the plugs--proper fuel pressure and fuel injector pulse.

The truck has been running fine with no problem. Since i had gotten it out of the shop. ( 4 weeks ago transfer case ) never had any problems out of it.

All I can do is help with some testing?

Gotcha

Hubby said he heard a buzzing noise from the relay box

Sometimes you can put hand on the relay, to feel the vibration so you know which relay. Then hopefully the relay box cover has a legend on it that tells you which relay is which. Then we check that wiring circuit for the relay. Knowing if you have spark at the plugs, engine cranking and proper fuel pressure and fuel injector pulse would help? If you missing everything, then I check proper cam and crank sensor signals. Unless you can do some testing, I'm not sure? Don't replace anything w/o doing some testing. Any applicable trouble codes?

Okay