I found the problem!!!
It because of 2 extra switch. I set their condition OFF when not flying TBM900.
However, when I load other airplane, when SimVIm loading, it will still catch these 2 switch's position, which in TBM900, landing and taxi light, ON.
That's why, everytime when I load, say C172, its landing and taxi switch will be ON position, regarding its actual switch position.
I thought, when I set an OFF condition, Simvim will totally ignore this switch, apparently, it's not.
Just for your reference.