turns over but won't start on 2006 Dodge Ram 2500

The trucks turns over fine, but won't start, any suggestions to what might be causing the problem?

If it turns over and doesn't start only two things possible, bad glow plugs or no fuel.

to check fuel, remove fuel line post fuel pump and turn over... see fuel.. then replace golw plugs and you should be back in business
2006 dodge 2500 5.9 do not have glow plugs. So I guess that is not the problem.