As far as the knocker goes:
1) Do a continuity check between the lugs on the coil. if no continuity, either a copper wire has come loose from one of the lugs, or the coil itself is bad. You might have a diode across the lugs that you can pull one side and check for a short, too.
2) Make sure the fuse is good.
3) Make sure the wiring is good to the board.
4) Find the drive transistor. Short the center tab to ground for just a second. If the coil is good, the transistor is good, and the power is good, the coil will fire. That also tells you the wiring from the transistor to the coil is fine and the problem lies in the signal from the CPU to the drive transistor. If it won't fire, try replacing the transistor first, then the coil...