Looking at yout switch... You have 3 terminals. I suspect that the bottom two is for the red side of your wire. You need to physically cut wire and crimp on a push on blade type connector on both sides of wire. The third terminal that is for allowing the led to lighy up i suspect and you need a wire from that terminal and use the plastic connector you have shown to the ground wire that goes back to black side of wire . if i remember correctly the wire bullet connectors on tractor wasnt color coded i think... You need to use the meter to confirm the positive. And negative side. Just be sure positive goes to switch on bottom terminals ans side terminals uses the pish connect on wire going back to negative side. Mind you.. Do all the cutting and splicing on the wire you ran side only. Never on tractor original wiring
