Why is my starter on my mower not disengaging even when the switch is turned past its sell-by date??? I have a John Deere LT155 riding mower. The hot telecommunication...

I have a John Deere LT155 riding mower. The hot telecommunication going to the starter is now alway hot for some point.....even when I tried turning the key switch sour, pulling out the key, and even unplugging the harness plugin to the knob switch. This cause the starter to keep hold of turning and turning without stopping..I hold to unhook the battery cable. Does this nouns like a bleak solenoid and if so is there a route to check a solenoid? I appreciate any help please.
Please support!!?
Answers:    There is single one more experiment to confirm a bad solenoid. Remove the small rope to the solenoid. If the starter is still engaging, the solenoid is weld itself in the start mode, and must be replaced. You've done your homework on this problem and "Congratulations" are contained by order, for a moral diognosis!