OK, we've got two things - the NON-START issue, and the "bad dash light" issue.
I'd fix the NON-START first. :) That's spark or gas, as noted. Any decent mechanic should be able to diagnose and fix that, it's not a MH issue, it's an internal combustion engine issue.k (EDIT: Or a DIESEL issue, now that I've read the previous comment... :)
The dash light is different. First, I'd confirm, that I'm drawing 12+ volts out of the batteries. Then you need to trace the power out of the light assembly itself, making sure that you have a good connection there (esp. the negative). Put a volt meter on the wires coming INTO the light to make sure you're sending volts to it.
Step by Step...