TNN 55 ignition switch

[aglee]

Installed a new ignition switch on a TN 55 Tractor. The tractor will start, but will not shut off.

 

[Fawken]

On some machines (including mine) the key doesn't shut it off. Diesels don't have ignitions so if no electric fuel pump or electric injectors or shut down solenoid you use the throttle to turn it off.
:welcome: to TBN

 

[TractorTech]

Installed a new ignition switch on a TN 55 Tractor. The tractor will start, but will not shut off.

Sounds like you connected the fuel shutoff solenoid wire to a positive leg on the switch OR the new switch is faulty.
Why did you replace the switch?

 

[PILOON]

Was the switch OEM or generic?
Generic might not be exactly the same connections, (but 'almost')
The shutoff solenoid would be a normally closed wanting a switched power connection.