suburban furnace won't turn off.

[Shmipshmop]

Hi all. wondering if you had experience with Suburban furnaces. I'm not sure I did anything in particular but as I was prepping for my trip this weekend, I was cycling through the systems and now my furnace will not turn off, not just the blower but the heating element. I have to pull the fuse or turn the unit off. Anyone else have this problem? But my real question is the on/off toggle on the furnace itself. when it is turned off, does that actually also control the gas flowing into the unit also? I'd like to use the trailer a couple more times before it sits on the lot for god knows how long to get it looked at. Any insight on trouble shooting? I replaced the thermostat just to see, but was wondering about the control board as a cause. Thanks. Furnace is a Suburban NT-20SEQ.