Joy, does it try to ignite at all? Tick tick tick tick, if yes does it start
for a few second, by start i mean can you hear the burner?

Do you have any flashing light (red)? The flashing red light will give you a
code related to a problem.

But try that first, find compress air and blow into the intake port under
the van. It's like an engine, it need good  fresh air from the intake port
(and a clean exhaust port at the same time), it need fuel (propane) and it
need electricity (12V), if the 12V volt is low it won't start. If you have
no propane it won't start but WILL give you a flashing red light, same for
low 12V.

Ben
http://www.benplace.com