Unfortunately it could be one or more of several things. 1st -is batteries turning it fast enough to crank it. 2nd check both batteries with volt meter to make sure BOTH are reading at least 12.5+ If one of them is too low it won't turn fast enough. 3rd Did you accidently move youre service light switch to off or to blackout? Be sure it's it UP position. This shouldnot affect whether it starts are not but you won't see any lights anywhere. Here again so many times, is the solonoid on fire wall clicking on when you turn key to start pos? If not, it could be blown and thus not heating up glow plugs. Simple way to find out if glow plugs are getting momentary power is to attach + red end line of volt meter to the wire going to anyone of glow plugs (just unplug it) and the - black end to a ground. When you turn key to start pos. look at meter. It should read up to 12v then maybe go down a little. If its NOT doing that then solonoid might be bad. try that see what happens & let us know.