Repairs system 7010 kill switch

[hotshot]

I have a 70 something landlord system 7010 and the key doesn't shut it off I have to pull the plug wire. There is also an empty spade connector on the switch any help would be greatly appreciated.

 

[reynoldston]

Negative power to the coil turns off tractor. Maybe a loose or broken wire to a ground on the chassis some place?