If the fused are good then you probably also have a relay in the circuit, you might check it to see if it gets energized.
Do you hear any ticking sound?
Probably no fuse for glow plugs, only for the relay and/or timer. They usually use fusible links for the power thru the relay to the plugs. You need to get information on your particular model to see how it operates instead of everyone guessing what could be wrong.
Didn't ask before, does the tractor start, you don't need them to start. On my 2815 the circuit covers the glow controller, fuel pump, alternator and couple other items is protected by the same 10 amp fuse.