OK. From the diagrams...
Power supply comes from F24 Red wire.
It has connections to the Climate Control (Black and White) (so probably only works if that's on and calling for heat) and the alternator (Blue and White) (charge light - so probably detects if engine is running).
There is a blower motor, a fuel pump, a glow plug, 2 temperature sensors and a flame sensor.
I have never seen one of these so can only make assumptions about how it works but it strikes me as being similar to an oil fired heating boiler:
Fan on
Glow plug on
Fuel pump on
Wait for a few seconds to see if it lights
If it lights, glow plug off, happy days.

If it doesn't light, fuel off, wait a while and try again. :-/
If a few attempts fail, shut down.

It has a diagnostic connector so I would expect a Tech 2 can probably interrogate fault codes from it... Stand by.. Yep, the Tech 2 does have an option to diagnose it. No idea what that tells you but I would have thought fault codes and perhaps live data that might give some clues.
Kevin