Greetings from GoVacuum,
Unfortunately there is no fuse on a Kirby Generation model. In my 10 years of repairing Kirby's as well as other vacuums I will tell you that 9 times out of 10, when a Kirby Generation doesn't turn on, it's the cord that needs to be replaced. This is by far the most common problem that we see on Kirby repairs.
The Kirby motor is very well built, and usually has a life of 30+ years (G3 is about 12-15 years now). The only other problem it could be on the Kirby would be carbon brushes, or the switch assembly.
I would first try testing the power cord, I think this will solve the problem for you. To test a cord on a Kirby Generation (all Generation models are the same machines, just different colors) first follow where the cord goes into the Kirby at the bottom. To access this cover easier, first remove the "boot" at the bottom of the outer bag. This is the plastic part at the bottom of the outer bag that connects onto the Kirby. You will see that there is a plastic cover over the cord. You will need to remove the screw that holds this cover on.
Now after you have removed the cover, pull the plug out of the machine. Once you have the cord disconnected from the machine, you can now test it to see if there is a short somewhere in the cord. You will need to purchase an inexpensive continuity tester from Home Depot, Radio Shack, or most other electronic stores. This will tell you if there is power running through the cord, or if the cord is bad. With the continuity tester, plug the cord into the wall outlet, then put the positive, and negative testing rods into the female end of the cord that plugs into the machine. You will then be able to tell if the cord has continuity going through it. The tester will indicate if there's continuity or not.
The picture here shows that the cord is good. If your tester does not light up, or indicate that there is continuity, you'll simply just need to purchase a new cord. As I stated earlier, this is the most common reason that a Kirby won't turn on.
If however your cord tests OK, this indicates that the machine either needs a new motor (or carbon brushes in the motor) or it needs a new switch.
Please feel free to email me if you'd like instructions on how to diagnosis the switch or carbon brushes, or if you need to purchase a cord for your G3. Also I can send you a parts diagram of the Kirby should you ever need any other part for it. I have all parts for Kirby in stock, and we are the cheapest price online.
If the cord tested ok, then there are a few other things that may have gone bad. I'd be more then happy to try and help you diagnosis the Kirby further. Please just request a repair clarifiaction here on Fixya with further details.
If this helped you figure out the problem, please rate my repair as helpful. I really do appreciate it, thank you.