manifold heater wiring

The wire that starts at the manifold heater - where does it go from there. I'm guessing the temporary (start) position on the ignition switch. Does the manifold heater use 12 volts? Thanks.

Sorry, my crystal ball is in the repair shop this week. What model tractor are you asking about?

My bad for assuming its a universal type diesel part. I have a Ford 420 Industrial, 3 cylinder.

It should be wired to its own terminal on the key switch with its own separate key position.

The "Run" position should have a terminal on the key switch that is connected to the instrument cluster to allow the gauges and warning lights to function. On a diesel, that is pretty much it. In a gasser it would also connect to the ignition circuit.

The "Start" position should only go to the starter solenoid.

Your 420 should have a hidden key position halfway between "Run" and "Start", and you have to hold the key there, halfway between the two positions against the spring pressure that would normally return it to the "Run" position when you release it. That hidden key position has its own separate terminal on the back of the key switch. Hold the key there for 30 seconds and see if the manifold heater is working. You can remove the hose going from the air filter to the manifold to actually see if it is dribbling fuel into the manifold and if it catches fire. That is how it works. It has an electric element in the heater tht heats up when it receives current,. and the heat opens a valve that allows fuel to drip in and then the heat from the element catches the fuel on fire.

Excellent information. Thank you.