on my popups, the on/off switch was on the bottom of the thermostat. never heard of a second switch.
you have to make sure you have the air purged out of the propane lines.
run your stove burners first, before firing up the furnace.
you also have to have a battery that's charged, to ignite the furnace. if the battery's weak, it may not light.
and Zoe the Wonder Dog(R.I.P.)
'07 Roo 23SS pushing an '07 Chevy Avalanche
Equalizer WDH and Prodigy BC