No Power to gauges, overhead msg center, or ECM????

I have a 2004 W900 w/ C15 Cat. For some reason or another today while in my shop, thank god, it decided to not start. It will crank over but I have no power to any of the gauges or the overhead message center. The check engine and stop engine light don't come on. I have been told that if they don't light up that u have no power to the ECM. I have checked the wires that go from the battery box to the fire wall the best I can and don't see anything wrong. I have tightened down my battery cables also. I have taken my key switch out and cleaned it up and put some electrical grease on the connections. I don't know if any of this is the problem but everything works for now. Does anyone have some other suggestions? For I don't believe that I have found the problem yet. Cause imagine this I went out to my truck tonight and turned the key on just to see what would happen and u know the rest of the story. Back to square one. Thanks Terrance

 

The truck will crank just wont fire up. I did check the fuses but didn't check the relays. Thanks

 

Hey I just went and checked my relay (ing bus) pulled it out and the truck does exactly what it did earlier today just cranks over and no start. Maybe Just that relay is going bad Thanks again