[ChuckS]

After furnace failed to light off and fan was running did you turn the thermostat completely off to clear lock out mode?

If so does fan run and no sound outside of DSI making popping sound to ignite when listening near exhaust?

If fan runs but you hear nothing it could be bad sail switch, bad overtemp switch or bad furnace control module

If this is an Atwood furnace locate control module and observe LED light to obtain error code..If Suburban there is no LED