Furnace Fan won't turn off, 2004 Alpha 40'

WildeOne wrote:
I am a new motorhome owner (8/2016). My furnace's blower would not turn off with the thermostat (blowing air, no heat) so I accessed the main switch through the outside panel to turn it off.

Is there a filter somewhere that could be clogged and causing the safety relay to turn off the heat and keep the fan blowing? I've poured over the book and opened every panel I can find and am confounded.

Thanks for any input.

Other than having your thermo setting for fan on, were you plugged in and/or were your batteries fully charged?
If in auto then it sounds like the sail sw. shut off the gas from lack of proper air flow and in which case the temp. setting couldn't be satisfied.
Hence a continuous run until the batteries are depleted completely.